Łupież różowy – Diagnostyka i diagnoza

Łupież różowy
Diagnostyka i diagnoza

Łupież różowy (pityriasis rosea) to samoograniczająca się dermatoza, charakteryzująca się początkowo pojawieniem się blaszki macierzystej o średnicy 2-5 cm, z rumieniowym, łuszczącym się obwodem i jaśniejszym środkiem, lokalizującej się głównie na tułowiu (w 90% przypadków). Po 1-2 tygodniach rozwija się uogólniona wysypka plamisto-grudkowa, z mniejszymi zmianami ułożonymi wzdłuż linii Langera, przypominającymi choinkę, obejmująca tułów i proksymalne części kończyn. Diagnostyka opiera się na obrazie klinicznym i badaniu fizykalnym, wspomagana dermatoskopią, która wykazuje żółtawe tło, obwodowe łuszczenie typu „collarette” oraz nieregularne rozmieszczenie punktowych naczyń. W diagnostyce różnicowej należy wykluczyć m.in. kiłę wtórną (testy RPR/VDRL), grzybicę (test KOH, posiew), łuszczycę kropelkową, liszaj płaski oraz inne dermatozy o podobnym obrazie klinicznym.

Diagnostyka łupieżu różowego

Łupież różowy (pityriasis rosea) to częsta, samoograniczająca się choroba skóry charakteryzująca się wysypką plamisto-grudkową, która zazwyczaj rozpoczyna się od wystąpienia pojedynczej większej zmiany zwanej blaszką macierzystą (herald patch), a następnie zajmuje tułów i proksymalne części kończyn. Diagnostyka tej jednostki chorobowej opiera się przede wszystkim na obrazie klinicznym oraz badaniu fizykalnym, jednak w niektórych przypadkach może wymagać dodatkowych badań w celu potwierdzenia rozpoznania lub wykluczenia innych schorzeń o podobnym obrazie klinicznym.¹²

Kliniczna diagnostyka łupieżu różowego

W większości przypadków doświadczony lekarz lub dermatolog może zdiagnozować łupież różowy wyłącznie na podstawie wyglądu wysypki. Klasyczny łupież różowy rozpoczyna się blaszką macierzystą na tułowiu (występuje w do 90% przypadków). Zmiana ta jest rumieniowa z nieco uniesionymi, łuszczącymi się brzegami i jaśniejszym, zanikowym środkiem. Jej wielkość wynosi zazwyczaj od 2 do 5 cm.¹²³

Po około 1-2 tygodniach od pojawienia się blaszki macierzystej występuje uogólniona wysypka składająca się z mniejszych, owalnych lub okrągłych zmian rumieniowych z łuszczeniem się, które układają się wzdłuż linii Langera, tworząc charakterystyczny obraz przypominający choinkę. Zmiany najczęściej lokalizują się na tułowiu i proksymalnych częściach kończyn.⁴⁵

Kryteria diagnostyczne

Ze względu na brak standaryzowanych wytycznych diagnostycznych oraz częste występowanie przypadków atypowych, zaproponowano zestaw kryteriów diagnostycznych dla łupieżu różowego.⁶⁷⁸

Do postawienia diagnozy pacjent musi spełnić wszystkie kryteria zasadnicze oraz przynajmniej jedno z kryteriów opcjonalnych, a także nie prezentować żadnego z kryteriów wykluczających:

Kryteria zasadnicze:

Dyskretne, okrągłe lub owalne zmiany⁹¹⁰
Złuszczanie na większości zmian¹¹
Obwodowe łuszczenie typu „collarette” z centralnym przejaśnieniem na co najmniej dwóch zmianach¹²

Kryteria opcjonalne (przynajmniej jedno z poniższych):

Rozmieszczenie na tułowiu i proksymalnych częściach kończyn (mniej niż 10% zmian dystalnie od środkowej części ramienia i środkowej części uda)¹³
Większość zmian ułożonych wzdłuż linii cięć skórnych¹⁴
Blaszka macierzysta pojawiająca się co najmniej 2 dni przed wystąpieniem pozostałych zmian¹⁵

Kryteria wykluczające:

Liczne małe pęcherzyki w centrum co najmniej dwóch zmian¹⁶
Co najmniej dwie zmiany na powierzchni dłoniowej lub podeszwowej¹⁷
Kliniczne lub serologiczne dowody na kiłę wtórną¹⁸

Badanie dermatoskopowe

Dermatoskopia może być pomocnym narzędziem w ocenie łupieżu różowego. Metoda ta pozwala na odróżnienie łupieżu różowego od innych schorzeń. W badaniu dermatoskopowym można zauważyć żółtawe tło, obwodowe ułożenie łusek oraz nieregularne rozmieszczenie punktowych naczyń.¹⁹

Badania dodatkowe

W większości przypadków łupieżu różowego nie ma potrzeby wykonywania dodatkowych badań diagnostycznych. Jednakże w sytuacjach, gdy obraz kliniczny jest nietypowy, rozpoznanie niepewne lub choroba nie ustępuje po 3-4 miesiącach, mogą być konieczne następujące badania:²⁰²¹

Badania laboratoryjne:

Badania serologiczne w kierunku kiły – ponieważ łupież różowy może być mylony z kiłą wtórną, zaleca się wykonanie testów RPR (Rapid Plasma Reagin) lub VDRL (Venereal Disease Research Laboratory), szczególnie u osób aktywnych seksualnie²²²³
Test na HIV – powinien być rozważony, szczególnie w przypadkach atypowych²⁴
Morfologia krwi – zwykle prawidłowa, choć u niektórych pacjentów można zaobserwować wzrost liczby białych krwinek, szczególnie limfocytów B, co może sugerować tło infekcyjne²⁵
OB (odczyn Biernackiego) – czasami obserwuje się podwyższone wartości jako marker stanu zapalnego²⁶

Badania mikrobiologiczne:

Test z wodorotlenkiem potasu (KOH) – wykonywany w celu wykluczenia zakażenia grzybiczego, które może imitować łupież różowy²⁷²⁸
Posiew grzybniczy – może być wykonany w celu wykluczenia grzybicy²⁹

Biopsja skóry

Biopsja skóry zazwyczaj nie jest konieczna, ale może być pomocna w wybranych sytuacjach. Wskazania do wykonania biopsji skóry obejmują:³⁰³¹

Atypowy przebieg choroby
Niepewne rozpoznanie
Brak ustąpienia zmian po 3-4 miesiącach
Konieczność różnicowania z innymi chorobami skóry

Procedura polega na pobraniu niewielkiego fragmentu tkanki ze zmiany po wcześniejszym znieczuleniu miejscowym. Pobrany materiał jest następnie analizowany pod mikroskopem.³²

Obraz histopatologiczny:

Badanie histopatologiczne wykazuje powierzchowne zapalenie skóry okołonaczyniowe. W naskórku obserwuje się ogniskową parakeratozę w formie zgrubień, hiperplazję i ogniskową spongiozę. W skórze właściwej widoczne są nacieki z limfocytów, histiocytów i rzadziej eozynofilów. Dodatkowo można zaobserwować wynaczynienie erytrocytów do powierzchownych warstw skóry.³³³⁴

W przypadku łupieżu różowego wywołanego lekami charakterystyczną cechą histopatologiczną jest obecność eozynofilów.³⁵

Diagnostyka różnicowa

Łupież różowy należy różnicować z wieloma innymi chorobami skóry, które mogą wykazywać podobny obraz kliniczny:³⁶³⁷³⁸

Kiła wtórna – określana jako „wielki naśladowca”, może wyglądać identycznie jak łupież różowy; zazwyczaj zajmuje również dłonie i podeszwy stóp
Łojotokowe zapalenie skóry
Wyprysk pieniążkowaty (nummularis)
Przyłuszczyca przewlekła (pityriasis lichenoides chronica)
Grzybica skóry gładkiej (tinea corporis) – blaszka macierzysta może być mylona z grzybicą
Łuszczyca kropelkowa (psoriasis guttata)
Wypryski wirusowe
Liszaj płaski (lichen planus)
Łupież podobny do łupieżu różowego wywołany lekami
Toczeń rumieniowaty podostry skórny (SCLE)
Łagodna purpura barwnikowa
Atopowe zapalenie skóry
Chłoniak skórny z komórek T (CTCL) – szczególnie w fazie plamistej może być mylony z łupieżem różowym

Szczególne sytuacje diagnostyczne

Łupież różowy u kobiet w ciąży

Kobiety w ciąży z łupieżem różowym powinny skonsultować się ze swoim położnikiem i dermatologiem ze względu na potencjalne ryzyko samoistnych poronień. Diagnostyka łupieżu różowego w ciąży jest taka sama jak u osób niebędących w ciąży.³⁹⁴⁰

Postaci atypowe

Łupież różowy może prezentować się w sposób atypowy, co utrudnia postawienie właściwego rozpoznania. Do atypowych prezentacji należą:⁴¹

Zmiany na twarzy, dłoniach i stopach
Zmiany pęcherzykowe – jak w przypadku pęcherzykowego łupieżu różowego, który jest rzadkim wariantem tej choroby
Nietypowa dystrybucja zmian
Brak blaszki macierzystej

W przypadku postaci atypowych częściej konieczne jest wykonanie badań dodatkowych, w tym biopsji skóry, w celu potwierdzenia rozpoznania.⁴²

Nawrotowy łupież różowy

Przed rozpoznaniem nawrotowego łupieżu różowego, kluczowe jest wykluczenie innych chorób, które mogą naśladować tę wysypkę, szczególnie jeśli obraz kliniczny różni się od typowego wzorca. Jeśli rozpoznanie pozostaje niepewne, wskazana może być biopsja skóry. Jednak ponieważ łupież różowy rzadko podlega biopsji, wiele przypadków określanych jako nawroty mogą w rzeczywistości nie być prawdziwymi nawrotami łupieżu różowego.⁴³

Podsumowanie diagnostyki łupieżu różowego

Rozpoznanie łupieżu różowego opiera się przede wszystkim na charakterystycznym obrazie klinicznym i jest głównie kliniczne. W typowych przypadkach doświadczony lekarz dermatolog może postawić diagnozę już podczas pierwszej wizyty. W przypadkach wątpliwych lub atypowych konieczne może być wykonanie dodatkowych badań, takich jak testy serologiczne w kierunku kiły, badania w kierunku zakażeń grzybiczych lub biopsja skóry.⁴⁴⁴⁵

Diagnostyka różnicowa jest istotna, ponieważ wiele innych schorzeń dermatologicznych może naśladować obraz kliniczny łupieżu różowego. Szczególną uwagę należy zwrócić na wykluczenie kiły wtórnej, zwłaszcza u osób aktywnych seksualnie.⁴⁶⁴⁷

Łupież różowy jest chorobą samoograniczającą się, która zazwyczaj ustępuje samoistnie w ciągu 2-12 tygodni. Jeśli jednak wysypka utrzymuje się dłużej niż 3 miesiące, pogarsza się lub występują nietypowe objawy, należy ponownie ocenić rozpoznanie i rozważyć wykonanie dodatkowych badań diagnostycznych.⁴⁸⁴⁹

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Materiały źródłowe

#1 Pityriasis Rosea: Diagnosis and Treatment | AAFP
https://www.aafp.org/pubs/afp/issues/2018/0101/p38.html
Pityriasis rosea is a common self-limiting rash that usually starts with a herald patch on the trunk and progresses along the Langer lines to a generalized rash over the trunk and limbs. The diagnosis is based on clinical and physical examination findings. The herald patch is an erythematous lesion with an elevated border and depressed center. The generalized rash usually presents two weeks after the herald patch. […] The diagnosis of pityriasis rosea is based on clinical and physical examination findings. Classic pityriasis rosea starts with a herald patch on the trunk in up to 90% of cases. The patch is erythematous with slightly elevated scaling borders and a lighter depressed center. […] If the diagnosis is uncertain, skin biopsy will help exclude other pathologies. The histology of pityriasis rosea will usually show focal parakeratosis, spongiosis, and acanthosis in the epidermis, and extravasated red blood cells with perivascular infiltrates of lymphocytes, monocytes, and eosinophils in the dermis.
#1 Pityriasis rosea – Diagnosis & treatment – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/pityriasis-rosea/diagnosis-treatment/drc-20376410
In most cases, your health care provider can identify pityriasis rosea by looking at the rash. You might need a scraping or possibly a skin biopsy, which involves taking a small piece of the rash for testing. This test can help tell a pityriasis rosea rash from other, similar rashes. […] Questions to ask your health care provider about pityriasis rosea include: […] What are other possible causes for my symptoms? […] Is this rash temporary or long lasting? […] Will this rash leave permanent scars? […] Will the rash cause permanent changes in skin color? […] What treatments are available, and which do you recommend? […] Will treatment for the rash interact with other treatments I’m receiving? […] What are possible side effects of this treatment? […] Will the treatment help ease the itching? If not, how can I treat the itching?
#2
https://ngdc.cncb.ac.cn/openlb/publication/OLB-PM-29365241
Pityriasis rosea is a common self-limiting rash that usually starts with a herald patch on the trunk and progresses along the Langer lines to a generalized rash over the trunk and limbs. The diagnosis is based on clinical and physical examination findings. The herald patch is an erythematous lesion with an elevated border and depressed center. The generalized rash usually presents two weeks after the herald patch. […] The differential diagnosis includes secondary syphilis, seborrheic dermatitis, nummular eczema, pityriasis lichenoides chronica, tinea corporis, viral exanthems, lichen planus, and pityriasis rosea-like eruption associated with certain medications. […] Treatment is aimed at controlling symptoms and consists of corticosteroids or antihistamines. In some cases, acyclovir can be used to treat symptoms and reduce the length of disease.
#2 Pityriasis Rosea: Diagnosis and Treatment | AAFP
https://www.aafp.org/pubs/afp/issues/2018/0101/p38.html
Pityriasis rosea is a common self-limiting rash that usually starts with a herald patch on the trunk and progresses along the Langer lines to a generalized rash over the trunk and limbs. The diagnosis is based on clinical and physical examination findings. The herald patch is an erythematous lesion with an elevated border and depressed center. The generalized rash usually presents two weeks after the herald patch. […] The diagnosis of pityriasis rosea is based on clinical and physical examination findings. Classic pityriasis rosea starts with a herald patch on the trunk in up to 90% of cases. The patch is erythematous with slightly elevated scaling borders and a lighter depressed center. […] If the diagnosis is uncertain, skin biopsy will help exclude other pathologies. The histology of pityriasis rosea will usually show focal parakeratosis, spongiosis, and acanthosis in the epidermis, and extravasated red blood cells with perivascular infiltrates of lymphocytes, monocytes, and eosinophils in the dermis.
#3 Pityriasis rosea – DermNet
https://dermnetnz.org/topics/pityriasis-rosea
How is pityriasis rosea diagnosed? […] Identification can be challenging at the onset of symptoms. There are no non-invasive tests that confirm the condition. The diagnosis is usually made clinically but may be supported by: […] Histology subacute dermatitis is seen on histology […] Eosinophils are typical of drug-induced pityriasis rosea. […] Blood testing for HHV6 (IgG or PCR) is not indicated because nearly 100% of individuals have been infected with the virus in childhood and commercial tests do not currently measure HHV6 activity. […] If the diagnosis is uncertain, especially if the palms and soles are affected, it is important to consider the possibility of other conditions. […] Proposed diagnostic criteria for pityriasis rosea […] Essential […] Discrete circular or oval lesions
#4
https://ngdc.cncb.ac.cn/openlb/publication/OLB-PM-29365241
Pityriasis rosea is a common self-limiting rash that usually starts with a herald patch on the trunk and progresses along the Langer lines to a generalized rash over the trunk and limbs. The diagnosis is based on clinical and physical examination findings. The herald patch is an erythematous lesion with an elevated border and depressed center. The generalized rash usually presents two weeks after the herald patch. […] The differential diagnosis includes secondary syphilis, seborrheic dermatitis, nummular eczema, pityriasis lichenoides chronica, tinea corporis, viral exanthems, lichen planus, and pityriasis rosea-like eruption associated with certain medications. […] Treatment is aimed at controlling symptoms and consists of corticosteroids or antihistamines. In some cases, acyclovir can be used to treat symptoms and reduce the length of disease.
#5 Pityriasis rosea
https://www.nhs.uk/conditions/pityriasis-rosea/
Pityriasis rosea is a common skin rash. It’s mild and usually goes away on its own without treatment. […] The main symptom of pityriasis rosea is a rash. […] The rash appears in 2 stages. […] The first stage of the rash is a single, scaly patch called a herald patch. […] A widespread rash of small, scaly spots appears about 5 to 15 days after you get the herald patch. […] After the rash has gone, you may have some darker or lighter areas of skin. This may be more obvious on brown or black skin. […] Other conditions can have similar symptoms to pityriasis rosea. […] Do not try to diagnose the problem yourself. See a GP if you’re worried. […] Pityriasis rosea usually gets better on its own within a few months without any treatment. […] If the rash is uncomfortable or itchy, a pharmacist might advise: using an emollient (moisturising treatment for the skin) on the rash.
#6 Pityriasis rosea – DermNet
https://dermnetnz.org/topics/pityriasis-rosea
How is pityriasis rosea diagnosed? […] Identification can be challenging at the onset of symptoms. There are no non-invasive tests that confirm the condition. The diagnosis is usually made clinically but may be supported by: […] Histology subacute dermatitis is seen on histology […] Eosinophils are typical of drug-induced pityriasis rosea. […] Blood testing for HHV6 (IgG or PCR) is not indicated because nearly 100% of individuals have been infected with the virus in childhood and commercial tests do not currently measure HHV6 activity. […] If the diagnosis is uncertain, especially if the palms and soles are affected, it is important to consider the possibility of other conditions. […] Proposed diagnostic criteria for pityriasis rosea […] Essential […] Discrete circular or oval lesions
#7
https://link.springer.com/article/10.1007/s40257-024-00915-7
Owing to the absence of standardized diagnostic guidelines and the frequent occurrence of atypical cases, Chuh et al. proposed a set of diagnostic criteria for pityriasis rosea. […] Dermoscopy can be a useful tool in the evaluation of PR. […] Histopathology can also be used as a diagnostic tool to confirm the diagnosis of PR in atypical cases and help differentiate PR from other similar-looking conditions. […] Several conditions may mimic PR and should be considered in the differential diagnosis. […] Before diagnosing recurrent PR, it is crucial to rule out other conditions that may mimic the rash, particularly if the presentation differs from the typical PR pattern. […] If the diagnosis remains uncertain, a skin biopsy may be useful. […] However, because PR is rarely biopsied, many cases labeled as recurrences may not be true PR recurrences. […] Thus, caution should be exercised when diagnosing recurrences without biopsy confirmation.
#8 Pityriasis Rosea | Mya Care
https://myacare.com/blog/pityriasis-rosea
Pityriasis rosea is a common self-limiting skin rash that usually lasts for about 5-10 weeks. […] The diagnosis of pityriasis rosea is straightforward, and is largely based on clinical history and physical examination. A blood test or skin punch biopsy is not recommended. […] In 2003, a criteria was proposed for the diagnosis of pityriasis rosea. To fulfill the criteria, a patient must have 3 essential features and at least 1 of the optional features. They also included 3 exclusion features. […] Essential features: Discrete circular or oval lesions, Scaling on most lesions, Peripheral collarette scaling with central clearance on at least 2 lesions. […] Optional features: Truncal and proximal limb distribution (10% of lesions distal to mid-upper-arm and mid-thigh), Most lesions along skin cleavage lines, Herald patch 2 days before other lesions. […] Exclusion features: Multiple small vesicles at the center of 2 lesions, 2 lesions on palmar or plantar skin surfaces.
#9 Pityriasis rosea – DermNet
https://dermnetnz.org/topics/pityriasis-rosea
How is pityriasis rosea diagnosed? […] Identification can be challenging at the onset of symptoms. There are no non-invasive tests that confirm the condition. The diagnosis is usually made clinically but may be supported by: […] Histology subacute dermatitis is seen on histology […] Eosinophils are typical of drug-induced pityriasis rosea. […] Blood testing for HHV6 (IgG or PCR) is not indicated because nearly 100% of individuals have been infected with the virus in childhood and commercial tests do not currently measure HHV6 activity. […] If the diagnosis is uncertain, especially if the palms and soles are affected, it is important to consider the possibility of other conditions. […] Proposed diagnostic criteria for pityriasis rosea […] Essential […] Discrete circular or oval lesions
#10 Pityriasis rosea – Wikipedia
https://en.wikipedia.org/wiki/Pityriasis_rosea
A set of validated diagnostic criteria for pityriasis rosea is as follows: A patient is diagnosed as having pityriasis rosea if: On at least one occasion or clinical encounter, the patient has all the essential clinical features and at least one of the optional clinical features, and On all occasions or clinical encounters related to the rash, the patient does not have any of the exclusional clinical features. […] The essential clinical features are the following: Discrete circular or oval lesions, Scaling on most lesions, and Peripheral collarette scaling with central clearance on at least two lesions. […] The optional clinical features are the following: Truncal and proximal limb distribution, with less than 10% of lesions distal to mid-upper-arm and mid-thigh, Orientation of most lesions along skin cleavage lines, and A herald patch (not necessarily the largest) appearing at least two days before eruption of other lesions, from history of the patient or from clinical observation. […] The exclusional clinical features are the following: Multiple small vesicles at the centre of two or more lesions, Two or more lesions on palmar or plantar skin surfaces, and Clinical or serological evidence of secondary syphilis.
#11 Pityriasis rosea – DermNet
https://dermnetnz.org/topics/pityriasis-rosea
Scaling on most lesions […] Peripheral collarette scaling with central clearance on at least two lesions […] Optional […] (At least one of the following features) […] Truncal and proximal limb distribution (10% of lesions distal to mid-upper-arm and mid-thigh) […] Most lesions along skin cleavage lines […] Herald patch 2 days before other lesions […] Exclusion […] Multiple small vesicles at the centre of 2 lesions […] 2 lesions on palmar or plantar skin surfaces.
#12 Pityriasis rosea – DermNet
https://dermnetnz.org/topics/pityriasis-rosea
Scaling on most lesions […] Peripheral collarette scaling with central clearance on at least two lesions […] Optional […] (At least one of the following features) […] Truncal and proximal limb distribution (10% of lesions distal to mid-upper-arm and mid-thigh) […] Most lesions along skin cleavage lines […] Herald patch 2 days before other lesions […] Exclusion […] Multiple small vesicles at the centre of 2 lesions […] 2 lesions on palmar or plantar skin surfaces.
#13 Pityriasis rosea – DermNet
https://dermnetnz.org/topics/pityriasis-rosea
Scaling on most lesions […] Peripheral collarette scaling with central clearance on at least two lesions […] Optional […] (At least one of the following features) […] Truncal and proximal limb distribution (10% of lesions distal to mid-upper-arm and mid-thigh) […] Most lesions along skin cleavage lines […] Herald patch 2 days before other lesions […] Exclusion […] Multiple small vesicles at the centre of 2 lesions […] 2 lesions on palmar or plantar skin surfaces.
#14 Pityriasis rosea – DermNet
https://dermnetnz.org/topics/pityriasis-rosea
Scaling on most lesions […] Peripheral collarette scaling with central clearance on at least two lesions […] Optional […] (At least one of the following features) […] Truncal and proximal limb distribution (10% of lesions distal to mid-upper-arm and mid-thigh) […] Most lesions along skin cleavage lines […] Herald patch 2 days before other lesions […] Exclusion […] Multiple small vesicles at the centre of 2 lesions […] 2 lesions on palmar or plantar skin surfaces.
#15 Pityriasis rosea – DermNet
https://dermnetnz.org/topics/pityriasis-rosea
Scaling on most lesions […] Peripheral collarette scaling with central clearance on at least two lesions […] Optional […] (At least one of the following features) […] Truncal and proximal limb distribution (10% of lesions distal to mid-upper-arm and mid-thigh) […] Most lesions along skin cleavage lines […] Herald patch 2 days before other lesions […] Exclusion […] Multiple small vesicles at the centre of 2 lesions […] 2 lesions on palmar or plantar skin surfaces.
#16 Pityriasis rosea – DermNet
https://dermnetnz.org/topics/pityriasis-rosea
Scaling on most lesions […] Peripheral collarette scaling with central clearance on at least two lesions […] Optional […] (At least one of the following features) […] Truncal and proximal limb distribution (10% of lesions distal to mid-upper-arm and mid-thigh) […] Most lesions along skin cleavage lines […] Herald patch 2 days before other lesions […] Exclusion […] Multiple small vesicles at the centre of 2 lesions […] 2 lesions on palmar or plantar skin surfaces.
#17 Pityriasis rosea – DermNet
https://dermnetnz.org/topics/pityriasis-rosea
Scaling on most lesions […] Peripheral collarette scaling with central clearance on at least two lesions […] Optional […] (At least one of the following features) […] Truncal and proximal limb distribution (10% of lesions distal to mid-upper-arm and mid-thigh) […] Most lesions along skin cleavage lines […] Herald patch 2 days before other lesions […] Exclusion […] Multiple small vesicles at the centre of 2 lesions […] 2 lesions on palmar or plantar skin surfaces.
#18 Pityriasis rosea – Wikipedia
https://en.wikipedia.org/wiki/Pityriasis_rosea
A set of validated diagnostic criteria for pityriasis rosea is as follows: A patient is diagnosed as having pityriasis rosea if: On at least one occasion or clinical encounter, the patient has all the essential clinical features and at least one of the optional clinical features, and On all occasions or clinical encounters related to the rash, the patient does not have any of the exclusional clinical features. […] The essential clinical features are the following: Discrete circular or oval lesions, Scaling on most lesions, and Peripheral collarette scaling with central clearance on at least two lesions. […] The optional clinical features are the following: Truncal and proximal limb distribution, with less than 10% of lesions distal to mid-upper-arm and mid-thigh, Orientation of most lesions along skin cleavage lines, and A herald patch (not necessarily the largest) appearing at least two days before eruption of other lesions, from history of the patient or from clinical observation. […] The exclusional clinical features are the following: Multiple small vesicles at the centre of two or more lesions, Two or more lesions on palmar or plantar skin surfaces, and Clinical or serological evidence of secondary syphilis.
#19 Pityriasis Rosea – StatPearls – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK448091/
Identify the characteristic skin presentations of pityriasis rosea (PR). […] Compare all the investigation options available for PR. […] Apply current evidence-based treatment options for PR. […] Implement interprofessional team strategies for improving care, coordination, and communication for patients with PR. […] Dermatoscopy helps differentiate PR from other conditions. This technique shows a yellowish background color, a peripheral arrangement of the scales, and a patchy distribution of loosely arranged dotted vessels. […] Histopathology shows superficial perivascular dermatitis. Focal parakeratosis in mounds, hyperplasia, and focal spongiosis are observed in the epidermis. […] PR is a self-limiting, exanthematous disease. Other than general measures like using moisturizers, bathing with soap alternatives, and cautiously exposing skin to sunlight without burning, some specific treatments may also be used. […] Timely diagnosis by a healthcare professional ensures appropriate guidance and reassurance, considering the generally favorable prognosis of pityriasis rosea.
#20 Pityriasis Rosea Workup: Laboratory Studies, Skin Biopsy and Histologic Findings
https://emedicine.medscape.com/article/1107532-workup
The diagnosis of pityriasis rosea (PR) is made clinically in most cases. In general, laboratory tests are not necessary or helpful, with a few exceptions. […] Because PR can be confused with secondary syphilis, a rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) test should be performed to rule out this condition. […] An HIV test should also be considered in these patients. […] Histologic examination is usually unnecessary, but may be useful in selected situations. A skin biopsy can be obtained when the eruption is atypical, the diagnosis is uncertain, or the disease has not resolved after 3-4 months.
#21 Pityriasis Rosea (Christmas Tree Rash): Causes & Treatment
https://my.clevelandclinic.org/health/diseases/17729-pityriasis-rosea
Pityriasis rosea is a common condition that causes discolored patches on your skin. […] Your healthcare provider can typically diagnose pityriasis rosea after a physical exam. However, pityriasis rosea can look similar to other skin conditions, including eczema (atopic dermatitis), psoriasis, including guttate psoriasis, ringworm, and tinea versicolor. […] If there’s any doubt, your healthcare provider may perform the following tests: allergy test, biopsy, blood tests to check for causes of a rash that aren’t related to pityriasis rosea.
#22 Pityriasis Rosea Workup: Laboratory Studies, Skin Biopsy and Histologic Findings
https://emedicine.medscape.com/article/1107532-workup
The diagnosis of pityriasis rosea (PR) is made clinically in most cases. In general, laboratory tests are not necessary or helpful, with a few exceptions. […] Because PR can be confused with secondary syphilis, a rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) test should be performed to rule out this condition. […] An HIV test should also be considered in these patients. […] Histologic examination is usually unnecessary, but may be useful in selected situations. A skin biopsy can be obtained when the eruption is atypical, the diagnosis is uncertain, or the disease has not resolved after 3-4 months.
#23 Pityriasis Rosea
https://www.cham.org/HealthwiseArticle.aspx?id=tr6164spec
Pityriasis rosea is usually harmless. […] Your doctor may be able to diagnose pityriasis rosea by looking at the rash. If the diagnosis is unclear, your doctor may do a potassium hydroxide (KOH) test. This test checks to make sure the rash is not caused by a fungal infection. A skin sample may be taken from the infected area and examined under the microscope (biopsy). […] In a sexually active person, a test for syphilis is often done.
#24 Pityriasis Rosea Workup: Laboratory Studies, Skin Biopsy and Histologic Findings
https://emedicine.medscape.com/article/1107532-workup
The diagnosis of pityriasis rosea (PR) is made clinically in most cases. In general, laboratory tests are not necessary or helpful, with a few exceptions. […] Because PR can be confused with secondary syphilis, a rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) test should be performed to rule out this condition. […] An HIV test should also be considered in these patients. […] Histologic examination is usually unnecessary, but may be useful in selected situations. A skin biopsy can be obtained when the eruption is atypical, the diagnosis is uncertain, or the disease has not resolved after 3-4 months.
#25 Azthena logo with the word Azthena
https://www.news-medical.net/health/Diagnosis-of-Pityriasis-Rosea.aspx
Pityriasis rosea is a common skin condition affecting 0.15% of the general population. This condition is more often than not diagnosed clinically by appearance and symptoms. […] Routine blood counts are prescribed. In most cases they are normal. Some patients may show a rise in white blood cell counts. In addition, there may be selective rise of lymphocytes (B lymphocytes) indicating that pityriasis rosea may be caused by an infection. There is also a raised Erythrocyte sedimentation rate (ESR) that is another marker of disease. […] Sometimes a skin biopsy may be undertaken to look at the cells of the lesion more closely. The skin area is cleaned and numbed with a local anaesthetic. Then a small tissue sample is cut off from the lesion. The area is dressed with bandages. […] Under the microscope the skin tissues with pityriasis rosea reveal infiltration of the skin cells with lymphocytes, histiocytes and rarely eosinophils. There are changes in the superficial cells of the skin called the epidermis with increased keratosis or dyskeratosis. In addition, some red blood cells may also be seen in the superficial skin layers. […] While diagnosing pityriasis rosea other conditions that may lead to similar lesions need to be ruled out.
#26 Azthena logo with the word Azthena
https://www.news-medical.net/health/Diagnosis-of-Pityriasis-Rosea.aspx
Pityriasis rosea is a common skin condition affecting 0.15% of the general population. This condition is more often than not diagnosed clinically by appearance and symptoms. […] Routine blood counts are prescribed. In most cases they are normal. Some patients may show a rise in white blood cell counts. In addition, there may be selective rise of lymphocytes (B lymphocytes) indicating that pityriasis rosea may be caused by an infection. There is also a raised Erythrocyte sedimentation rate (ESR) that is another marker of disease. […] Sometimes a skin biopsy may be undertaken to look at the cells of the lesion more closely. The skin area is cleaned and numbed with a local anaesthetic. Then a small tissue sample is cut off from the lesion. The area is dressed with bandages. […] Under the microscope the skin tissues with pityriasis rosea reveal infiltration of the skin cells with lymphocytes, histiocytes and rarely eosinophils. There are changes in the superficial cells of the skin called the epidermis with increased keratosis or dyskeratosis. In addition, some red blood cells may also be seen in the superficial skin layers. […] While diagnosing pityriasis rosea other conditions that may lead to similar lesions need to be ruled out.
#27 Pityriasis Rosea
https://www.cham.org/HealthwiseArticle.aspx?id=tr6164spec
Pityriasis rosea is usually harmless. […] Your doctor may be able to diagnose pityriasis rosea by looking at the rash. If the diagnosis is unclear, your doctor may do a potassium hydroxide (KOH) test. This test checks to make sure the rash is not caused by a fungal infection. A skin sample may be taken from the infected area and examined under the microscope (biopsy). […] In a sexually active person, a test for syphilis is often done.
#28 Pityriasis Rosea
https://www.myactivehealth.com/hwcontent/content/special/tr6164spec.html
Your doctor will diagnose pityriasis rosea by looking at the rash. Diagnosis can be hard when only the herald patch is visible, because the condition is often mistaken for ringworm or eczema at this time. After the rash appears, diagnosis is generally clear. […] If the diagnosis is unclear, your doctor may do a potassium hydroxide (KOH) test to make sure the rash is not caused by a fungal infection. A skin sample may be taken from the infected area and examined under the microscope (biopsy). If the diagnosis is unclear in a sexually active person, a test for syphilis is often done.
#29 Pityriasis rosea – Symptoms, diagnosis and treatment | BMJ Best Practice US
https://bestpractice.bmj.com/topics/en-us/279
Pityriasis rosea is an inflammatory skin disease with unclear etiology, although an infectious cause has been suggested. […] Can present in patients of any age but most often in people ages 10 to 35 years. […] Manifests as an acute, self-limited, inflammatory eruption characterized in the majority of patients by a single larger lesion, the herald patch, followed by eruption of smaller papulosquamous oval lesions. […] Symptoms are treated by topical corticosteroids and/or oral antihistamines, or ultraviolet therapy. […] Key diagnostic factors include herald patch, pruritus, age 10 to 35 years, 2- to 12-week duration, scale, located on trunk and upper extremities, fir-tree pattern distribution, located on face, palms, soles, mucosa, and acute to subacute recurrent skin eruption. […] Other diagnostic factors include 2-week timing between herald patch and new lesions, female sex, prodromal symptoms, and pigmentary alteration (severe cases/dark skin color). […] Tests to consider include skin biopsy, antistreptolysin O titers, potassium hydroxide (KOH) prep microscopy or fungal culture, and rapid plasma reagin/Venereal Disease Research Laboratory.
#30 Pityriasis Rosea Workup: Laboratory Studies, Skin Biopsy and Histologic Findings
https://emedicine.medscape.com/article/1107532-workup
The diagnosis of pityriasis rosea (PR) is made clinically in most cases. In general, laboratory tests are not necessary or helpful, with a few exceptions. […] Because PR can be confused with secondary syphilis, a rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) test should be performed to rule out this condition. […] An HIV test should also be considered in these patients. […] Histologic examination is usually unnecessary, but may be useful in selected situations. A skin biopsy can be obtained when the eruption is atypical, the diagnosis is uncertain, or the disease has not resolved after 3-4 months.
#31 Pityriasis rosea – Dermatology Advisor
https://www.dermatologyadvisor.com/home/decision-support-in-medicine/dermatology/pityriasis-rosea/
Pityriasis rosea is an acute, self-limited exanthem characterized classically by the eruption of a well-circumscribed, pink, oval, scaling patch, or herald patch that is usually several centimeters in diameter. […] Diagnosis is based primarily on history and physical examination alone. A skin biopsy may be necessary to support the diagnosis as it can mimic many other conditions. […] Differential diagnosis of pityriasis rosea includes tinea corporis, tinea versicolor, pityriasis lichenoides chronica, guttate psoriasis, syphilis, nummular eczema, subacute cutaneous lupus erythematosis (SCLE), benign pigmented purpura, atopic dermatitis, digitate dermatoses, cutaneous T-cell lymphoma (CTCL) and pityriasis lichenoides. […] Secondary syphilis, frequently termed the great imitator, can look identical to pityriasis rosea and may be missed if the physician does not have a high index of suspicion. […] Patch stage CTCL, especially presentations with digitate lesions mimicking digitate dermatosis, can easily be mistaken for pityriasis rosea during initial evaluation. […] A biopsy may be warranted in this situation or in any atypical presentation.
#32 Azthena logo with the word Azthena
https://www.news-medical.net/health/Diagnosis-of-Pityriasis-Rosea.aspx
Pityriasis rosea is a common skin condition affecting 0.15% of the general population. This condition is more often than not diagnosed clinically by appearance and symptoms. […] Routine blood counts are prescribed. In most cases they are normal. Some patients may show a rise in white blood cell counts. In addition, there may be selective rise of lymphocytes (B lymphocytes) indicating that pityriasis rosea may be caused by an infection. There is also a raised Erythrocyte sedimentation rate (ESR) that is another marker of disease. […] Sometimes a skin biopsy may be undertaken to look at the cells of the lesion more closely. The skin area is cleaned and numbed with a local anaesthetic. Then a small tissue sample is cut off from the lesion. The area is dressed with bandages. […] Under the microscope the skin tissues with pityriasis rosea reveal infiltration of the skin cells with lymphocytes, histiocytes and rarely eosinophils. There are changes in the superficial cells of the skin called the epidermis with increased keratosis or dyskeratosis. In addition, some red blood cells may also be seen in the superficial skin layers. […] While diagnosing pityriasis rosea other conditions that may lead to similar lesions need to be ruled out.
#33 Azthena logo with the word Azthena
https://www.news-medical.net/health/Diagnosis-of-Pityriasis-Rosea.aspx
Pityriasis rosea is a common skin condition affecting 0.15% of the general population. This condition is more often than not diagnosed clinically by appearance and symptoms. […] Routine blood counts are prescribed. In most cases they are normal. Some patients may show a rise in white blood cell counts. In addition, there may be selective rise of lymphocytes (B lymphocytes) indicating that pityriasis rosea may be caused by an infection. There is also a raised Erythrocyte sedimentation rate (ESR) that is another marker of disease. […] Sometimes a skin biopsy may be undertaken to look at the cells of the lesion more closely. The skin area is cleaned and numbed with a local anaesthetic. Then a small tissue sample is cut off from the lesion. The area is dressed with bandages. […] Under the microscope the skin tissues with pityriasis rosea reveal infiltration of the skin cells with lymphocytes, histiocytes and rarely eosinophils. There are changes in the superficial cells of the skin called the epidermis with increased keratosis or dyskeratosis. In addition, some red blood cells may also be seen in the superficial skin layers. […] While diagnosing pityriasis rosea other conditions that may lead to similar lesions need to be ruled out.
#34 Pityriasis Rosea – StatPearls – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK448091/
Identify the characteristic skin presentations of pityriasis rosea (PR). […] Compare all the investigation options available for PR. […] Apply current evidence-based treatment options for PR. […] Implement interprofessional team strategies for improving care, coordination, and communication for patients with PR. […] Dermatoscopy helps differentiate PR from other conditions. This technique shows a yellowish background color, a peripheral arrangement of the scales, and a patchy distribution of loosely arranged dotted vessels. […] Histopathology shows superficial perivascular dermatitis. Focal parakeratosis in mounds, hyperplasia, and focal spongiosis are observed in the epidermis. […] PR is a self-limiting, exanthematous disease. Other than general measures like using moisturizers, bathing with soap alternatives, and cautiously exposing skin to sunlight without burning, some specific treatments may also be used. […] Timely diagnosis by a healthcare professional ensures appropriate guidance and reassurance, considering the generally favorable prognosis of pityriasis rosea.
#35 Pityriasis rosea – DermNet
https://dermnetnz.org/topics/pityriasis-rosea
How is pityriasis rosea diagnosed? […] Identification can be challenging at the onset of symptoms. There are no non-invasive tests that confirm the condition. The diagnosis is usually made clinically but may be supported by: […] Histology subacute dermatitis is seen on histology […] Eosinophils are typical of drug-induced pityriasis rosea. […] Blood testing for HHV6 (IgG or PCR) is not indicated because nearly 100% of individuals have been infected with the virus in childhood and commercial tests do not currently measure HHV6 activity. […] If the diagnosis is uncertain, especially if the palms and soles are affected, it is important to consider the possibility of other conditions. […] Proposed diagnostic criteria for pityriasis rosea […] Essential […] Discrete circular or oval lesions
#36
https://ngdc.cncb.ac.cn/openlb/publication/OLB-PM-29365241
Pityriasis rosea is a common self-limiting rash that usually starts with a herald patch on the trunk and progresses along the Langer lines to a generalized rash over the trunk and limbs. The diagnosis is based on clinical and physical examination findings. The herald patch is an erythematous lesion with an elevated border and depressed center. The generalized rash usually presents two weeks after the herald patch. […] The differential diagnosis includes secondary syphilis, seborrheic dermatitis, nummular eczema, pityriasis lichenoides chronica, tinea corporis, viral exanthems, lichen planus, and pityriasis rosea-like eruption associated with certain medications. […] Treatment is aimed at controlling symptoms and consists of corticosteroids or antihistamines. In some cases, acyclovir can be used to treat symptoms and reduce the length of disease.
#37 Pityriasis Rosea: Causes, Symptoms, Stages, & Treatment
https://www.medicinenet.com/pityriasis_rosea/article.htm
Pityriasis rosea may be misdiagnosed as the following: Psoriasis, Eczema, Fungal infection (tinea corporis), Secondary syphilis, Drug eruption (a diffuse body rash caused commonly by a reaction to medications like an oral antibiotic), Fixed drug eruption (a single small, circular, or oval patch of skin rash caused by taking a medication), Pityriasis lichenoides chronica, Parapsoriasis, Lichen planus, HIV seroconversion rash.
#38 Pityriasis rosea – Dermatology Advisor
https://www.dermatologyadvisor.com/home/decision-support-in-medicine/dermatology/pityriasis-rosea/
Pityriasis rosea is an acute, self-limited exanthem characterized classically by the eruption of a well-circumscribed, pink, oval, scaling patch, or herald patch that is usually several centimeters in diameter. […] Diagnosis is based primarily on history and physical examination alone. A skin biopsy may be necessary to support the diagnosis as it can mimic many other conditions. […] Differential diagnosis of pityriasis rosea includes tinea corporis, tinea versicolor, pityriasis lichenoides chronica, guttate psoriasis, syphilis, nummular eczema, subacute cutaneous lupus erythematosis (SCLE), benign pigmented purpura, atopic dermatitis, digitate dermatoses, cutaneous T-cell lymphoma (CTCL) and pityriasis lichenoides. […] Secondary syphilis, frequently termed the great imitator, can look identical to pityriasis rosea and may be missed if the physician does not have a high index of suspicion. […] Patch stage CTCL, especially presentations with digitate lesions mimicking digitate dermatosis, can easily be mistaken for pityriasis rosea during initial evaluation. […] A biopsy may be warranted in this situation or in any atypical presentation.
#39 Pityriasis Rosea – Skin of Color Society
https://skinofcolorsociety.org/discover-patients-public/patient-education/pityriasis-rosea
Dermatologists can typically diagnose pityriasis rosea based on the appearance of the rash. […] Scraping or biopsy may be performed in some cases to confirm the diagnosis. […] Pregnant individuals with pityriasis rosea should consult their obstetrician and dermatologist due to the risk of spontaneous abortions. […] Doctors can usually tell by looking at the rash. […] Sometimes, they might need to scrape or check a small piece of the rash. […] If someone is pregnant and has this rash, they should talk to their doctor.
#40 Pityriasis rosea – Symptoms, diagnosis and treatment | BMJ Best Practice US
https://bestpractice.bmj.com/topics/en-us/279
Pityriasis rosea is an inflammatory skin disease with unclear etiology, although an infectious cause has been suggested. […] Can present in patients of any age but most often in people ages 10 to 35 years. […] Manifests as an acute, self-limited, inflammatory eruption characterized in the majority of patients by a single larger lesion, the herald patch, followed by eruption of smaller papulosquamous oval lesions. […] Symptoms are treated by topical corticosteroids and/or oral antihistamines, or ultraviolet therapy. […] Key diagnostic factors include herald patch, pruritus, age 10 to 35 years, 2- to 12-week duration, scale, located on trunk and upper extremities, fir-tree pattern distribution, located on face, palms, soles, mucosa, and acute to subacute recurrent skin eruption. […] Other diagnostic factors include 2-week timing between herald patch and new lesions, female sex, prodromal symptoms, and pigmentary alteration (severe cases/dark skin color). […] Tests to consider include skin biopsy, antistreptolysin O titers, potassium hydroxide (KOH) prep microscopy or fungal culture, and rapid plasma reagin/Venereal Disease Research Laboratory.
#41 Pityriasis rosea: Symptoms, diagnosis, and treatment
https://www.medicalnewstoday.com/articles/318281
Pityriasis rosea may be said to be atypical when the diagnosis has been difficult. An atypical pityriasis rosea rash is often marked by: […] If a doctor is in doubt over the diagnosis, they may refer the individual to a skin specialist (dermatologist).
#42 Vesicular pityriasis rosea | Cleveland Clinic Journal of Medicine
https://www.ccjm.org/content/92/2/81
A 37-year-old man presented to the dermatology clinic with a 9-day history of disseminated pruritic rash on his trunk and extremities. […] Vesicular pityriasis rosea was diagnosed based mainly on the clinical features of the rash, including erythematous papulosquamous lesions aligning with dermoid lines and a herald patch on the trunk, both typical of pityriasis rosea, and the presence of vesicular lesions. […] The results of the histopathologic examination were also consistent with pityriasis rosea, and laboratory testing helped exclude other possible diagnoses. […] The presence of vesicles surrounding the lesions pointed to a diagnosis of vesicular pityriasis rosea, an atypical variant of pityriasis rosea. […] Diagnosis of these disorders involves comprehensive evaluations, including clinical features, histologic examination, and immunohistologic assessment.
#43
https://link.springer.com/article/10.1007/s40257-024-00915-7
Owing to the absence of standardized diagnostic guidelines and the frequent occurrence of atypical cases, Chuh et al. proposed a set of diagnostic criteria for pityriasis rosea. […] Dermoscopy can be a useful tool in the evaluation of PR. […] Histopathology can also be used as a diagnostic tool to confirm the diagnosis of PR in atypical cases and help differentiate PR from other similar-looking conditions. […] Several conditions may mimic PR and should be considered in the differential diagnosis. […] Before diagnosing recurrent PR, it is crucial to rule out other conditions that may mimic the rash, particularly if the presentation differs from the typical PR pattern. […] If the diagnosis remains uncertain, a skin biopsy may be useful. […] However, because PR is rarely biopsied, many cases labeled as recurrences may not be true PR recurrences. […] Thus, caution should be exercised when diagnosing recurrences without biopsy confirmation.
#44 Pityriasis rosea: Diagnosis and treatment
https://www.aad.org/public/diseases/a-z/pityriasis-rosea-treatment
Pityriasis rosea causes a rash that will clear on its own, so most people dont need treatment. […] A dermatologist will look at your rash and ask questions about your health. If you have the classic pityriasis rosea rash, a dermatologist can often diagnose you right away. To the trained eye, this rash is obvious. […] Sometimes, testing is necessary to rule out another condition, such as an infection. When testing is necessary, your dermatologist may remove a bit of skin or order a blood test.
#45 Pityriasis rosea
https://www.nhs.uk/conditions/pityriasis-rosea/
Pityriasis rosea is a common skin rash. It’s mild and usually goes away on its own without treatment. […] The main symptom of pityriasis rosea is a rash. […] The rash appears in 2 stages. […] The first stage of the rash is a single, scaly patch called a herald patch. […] A widespread rash of small, scaly spots appears about 5 to 15 days after you get the herald patch. […] After the rash has gone, you may have some darker or lighter areas of skin. This may be more obvious on brown or black skin. […] Other conditions can have similar symptoms to pityriasis rosea. […] Do not try to diagnose the problem yourself. See a GP if you’re worried. […] Pityriasis rosea usually gets better on its own within a few months without any treatment. […] If the rash is uncomfortable or itchy, a pharmacist might advise: using an emollient (moisturising treatment for the skin) on the rash.
#46 Pityriasis Rosea Workup: Laboratory Studies, Skin Biopsy and Histologic Findings
https://emedicine.medscape.com/article/1107532-workup
The diagnosis of pityriasis rosea (PR) is made clinically in most cases. In general, laboratory tests are not necessary or helpful, with a few exceptions. […] Because PR can be confused with secondary syphilis, a rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) test should be performed to rule out this condition. […] An HIV test should also be considered in these patients. […] Histologic examination is usually unnecessary, but may be useful in selected situations. A skin biopsy can be obtained when the eruption is atypical, the diagnosis is uncertain, or the disease has not resolved after 3-4 months.
#47 Pityriasis rosea – Dermatology Advisor
https://www.dermatologyadvisor.com/home/decision-support-in-medicine/dermatology/pityriasis-rosea/
Pityriasis rosea is an acute, self-limited exanthem characterized classically by the eruption of a well-circumscribed, pink, oval, scaling patch, or herald patch that is usually several centimeters in diameter. […] Diagnosis is based primarily on history and physical examination alone. A skin biopsy may be necessary to support the diagnosis as it can mimic many other conditions. […] Differential diagnosis of pityriasis rosea includes tinea corporis, tinea versicolor, pityriasis lichenoides chronica, guttate psoriasis, syphilis, nummular eczema, subacute cutaneous lupus erythematosis (SCLE), benign pigmented purpura, atopic dermatitis, digitate dermatoses, cutaneous T-cell lymphoma (CTCL) and pityriasis lichenoides. […] Secondary syphilis, frequently termed the great imitator, can look identical to pityriasis rosea and may be missed if the physician does not have a high index of suspicion. […] Patch stage CTCL, especially presentations with digitate lesions mimicking digitate dermatosis, can easily be mistaken for pityriasis rosea during initial evaluation. […] A biopsy may be warranted in this situation or in any atypical presentation.
#48 Pityriasis rosea – Symptoms & causes – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/pityriasis-rosea/symptoms-causes/syc-20376405
Pityriasis rosea typically begins with a large, slightly raised, scaly patch called the herald patch. […] See your health care provider if you develop a rash that gets worse or hasn’t cleared up in three months. […] The exact cause of pityriasis rosea is unclear. It might be triggered by an infection with a virus, particularly by certain strains of the herpes virus. […] Having family members with pityriasis rosea increases your risk of developing the condition. […] Complications of pityriasis rosea aren’t likely. If they do occur, they may include: Severe itching. […] Skin biopsy.
#49 Pityriasis rosea
https://www.nhs.uk/conditions/pityriasis-rosea/
If these treatments do not work or if you have severe pityriasis rosea, your GP may recommend steroid cream or refer you to a skin specialist (dermatologist). […] See a GP if you have a rash that’s still itchy after trying pharmacy treatments like emollients or antihistamines. […] See a GP if you have a rash that has not gone away after 3 months.