11/14/24, 10\:50 AM Pityriasis Rosea

Pityriasis Rosea

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Pityriasis rosea\: a common, self-limiting rash that usually follows a viral infection, most frequently seen in patients aged 10-
35 years.
Aetiology\: Associated with human herpesvirus (HHV), particularly HHV-6 and HHV-7. The exact cause remains unknown
and evidence is con
Clinical features\:
Prodrome\: mild fever, headache, malaise, pharyngitis, joint pain.
Herald patch\: a singular salmon-coloured, scaly lesion (2-5 cm) that clears centrally, commonly on the trunk.
Widespread rash\: develops 5-15 days after the herald patch, smaller lesions (0.5-1 cm) with a scaly outer border, often in a
Christmas tree pattern along Langer’s lines.
Di
Guttate psoriasis\: No herald patch, coarse silver scale.
Pityriasis versicolor\: Associated with hot/humid conditions,
Tinea corporis\: Slower-growing large patch, similar to herald patch but not followed by widespread rash.
Others\: discoid eczema, secondary syphilis, HIV seroconversion, lichen planus, drug reactions.
Investigations\:
Skin scrapings\: to rule out fungal causes.
Skin biopsy.
Management\:
Conservative\: reassurance (not contagious, will resolve on its own, avoid heat exposure).
Symptomatic relief\: emollients, topical corticosteroids, antihistamines.
Other options\: dermatology referral for uncertain diagnosis, atypical rash, or persistence beyond three months; severe
cases may require UV-B phototherapy or oral acyclovir.
Complications\:
Temporary hypo- or hyperpigmentation after rash resolution, especially in darker skin.
First 15 weeks of pregnancy\: associated with miscarriage, premature delivery, neonatal hypotonia.
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Introduction

Pityriasis rosea is a common rash that is thought to occur after a viral infection. Characteristically scaly and pink-coloured,
pityriasis rosea is usually self-limiting and occurs most frequently among patients aged 10-35 years.
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Aetiology

While the exact cause of pityriasis rosea is unknown, it is believed to be associated with certain viruses. Chie
association has been found between pityriasis rosea and human herpesvirus (HHV), in particular, HHV-6 and HHV-7.
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However, it is important to note that evidence on this association, is con
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Pityriasis rosea can occur in clusters such as schools and families; however, the rash is not contagious and there is no
genetic component.

Clinical features

History

The typical history of a patient with pityriasis rosea follows a sequence of stages including prodromal symptoms, a herald
patch and
Prodrome
The prodromal phase usually lasts a few days and includes mild fever, headache, malaise, pharyngitis and joint pain.
Herald patch
In 50% of all cases, the
known as a ‘herald patch’ (Figure 1).
Widespread rash
Approximately 5-15 days after the development of the herald patch, a widespread rash appears and continues to develop
over 2-6 weeks (Figures 2 & 3). This rash may be pruritic but it is not typically painful.

Clinical examination

A thorough dermatological examination is required for all patients presenting with clinical features of pityriasis rosea.
Herald patch
Typical clinical appearances of the herald patch are as follows\:
Site\: commonly located on the trunk but may also be present on the face, feet and hands
Size\: diameter of approximately 2-5cm
Con
Colour\: the lesion appears pale pink on light skin and can appear dark brown or grey on darker skin
Morphology\: patch or plaque (if the border is raised and palpable)
Figure 1. Herald patch
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Widespread rash
Typical clinical features of the widespread rash which follows the herald patch are as follows\:
Site and distribution\: usually found on the trunk and proximal limbs. The distribution is often symmetrical and occurs
along Langer’s lines of the trunk, with an appearance resembling the branches of a Christmas tree
Size\: smaller than the herald patch with each lesion measuring approximately 0.5-1 cm
Con
Colour\: the lesions appear pale pink on light skin, but may appear grey or dark brown on darker skin
Morphology\: patch or plaque (if the border is raised and palpable)
The widespread rash gradually fades over 6-8 weeks but, in some people, can last up to
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Atypical forms of pityriasis rosea can develop such as inverse pityriasis rosea where rashes occur on the face and
extremities with sparing of the trunk. See this link for more information on the less common forms of pityriasis rosea.
Figure 2. The widespread rash of pityriasis rosea as seen on light skin 5
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Figure 3. The widespread rash of pityriasis rosea as seen on dark skin
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Di

Condition Similarities Di
Guttate
psoriasis
History\: may have a previous
history of S t r e p t o c o c c a l infection
Location\: rash commonly
appears on the trunk and
proximal limbs
Appearance\: multiple pink and
scaly lesions which have a small
diameter of 2-10mm
History\: no history of a herald patch
preceding the widespread rash
Location\: rash does not speci
occur along the cleavage lines of the
trunk
Appearance\: scale appears to be
coarse with a silver appearance and
occurs across the whole lesion as
opposed to just the border
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Pityriasis
versicolou
r
History\: rash may be itchy
Location\: often a
and proximal limbs
Appearance\: multiple small
lesions with a
circumference. Often results in
hypopigmentation on dark skin
which can also occur in pityriasis
rosea.
History\: more commonly occurs in
summer months and is associated
with hot and humid conditions
Location\: rash doesn’t speci
occur along the cleavage lines of the
trunk
Appearance\: no scale present and
discrete lesions may develop and
become con
Tinea
corporis
(ringworm)
History\: rash may be itchy
Appearance\: the herald patch is
very similar to the patches which
develop in ringworm due to its
size, round shape and raised
border of
History\: the large patch in ringworm
is not followed by smaller discrete
lesions. This lesion is slower growing
and develops over a longer period.
Appearance\: very similar to that of
the herald patch seen in pityriasis
rosea but is not similar to the
widespread rash that follows
Other di
planus and drug reactions.

Investigations

Pityriasis rosea is a clinical diagnosis, however, if there is clinical uncertainty, the following investigations can be performed
to rule out other di
Skin scrapings\: to rule out fungal causes such as tinea corporis
Skin biopsy

Management

Pityriasis rosea is a self-limiting condition and should resolve without treatment, therefore management typically involves
reassurance, advice and symptomatic relief.

Conservative management

Some general points of reassurance include\:
the rash is not contagious
children can go to school
the rash should resolve on its own
the rash should not leave scarring
Advise the patient to avoid exposing the rash to heat such as hot showers, hot baths and vigorous exercise.

Symptomatic relief

The following therapies can be used alone or in combination to manage the symptoms associated with pityriasis rosea\:
Emollients can be used to moisturise and soothe the skin
Topical corticosteroids can be used to reduce itching and in
Antihistamines can be taken to reduce itching
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Other management options

Consider a dermatology referral if\:
The diagnosis is uncertain
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The rash is atypical (e.g. a rash on the extremities or the presence of secondary features such as urticaria or petechiae)
The rash persists beyond three months
Severe cases of pityriasis rosea sometimes require\:
UV-B phototherapy
Oral acyclovir
Severe cases should be managed by a dermatologist.

Acne vulgaris

Complications

Basal Cell Carcinoma (BCC)
After the resolution of the rash, patients may develop temporary hypo- or hyperpigmentation but this should not cause
Cellulitis
permanent scarring. This is more common in patients with darker skin.
Cutaneous Squamous Cell Carcinoma (SCC)
In some cases, the development of pityriasis rosea in the
Erythema Multiforme
miscarriage, premature delivery and neonatal hypotonia.
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Test yourself

References

British Association of Dermatologists. P i t y r i a s i s r o s e a . Published in 2019. Available from\: [LINK]
Introduction
Watanabe T., Kawamura T., Aquilino E.A., Blauvelt A., Jacob S.E., Orenstein J.M., Black J.B. P i t y r i a s i s R o s e a i s A s s o c i a t e d w i t h
S y s t e m i c A c t i v e I n f e c t i o n w i t h B o t h H u m a n H e r p e s v i r u s- 7 a n d H u m a n H e r p e s v i r u s-6 . Published in 2002. Available from\:
Aetiology
[LINK]
Kempf W., Adams V., Kleinhans M., Burg G., Panizzon R.G., Campadelli-Fiume G., Nestle F.O. P i t y r i a s i s R o s e a I s N o t
Clinical features
A s s o c i a t e d W i t h H u m a n H e r p e s v i r u s 7 . Published in 1999. Available from\: [LINK]
Heilman J.. A h e r a l d p a t c h o f p i t y r i a s i s r o s e a . Licence\: CC-BY-SA-3.0. Available from\: [LINK]
Di
Heilman J.. P i t y r i a s i s r o s e a . Licence\: CC-BY-SA-3.0. Available from\: [LINK]
Blyth M.. P i t y r i a s i s r o s e a i n a N i g e r i a n b o y . Licence\: CC-BY-3.0. Available from\: [LINK]
Investigations
Urbina F., Das A., Sudy E.. C l i n i c a l v a r i a n t s o f p i t y r i a s i s r o s e a . Published in 2017. Available from\: [LINK]
Management
P i t y r i a s i s r o s e a . Published in 2020. Available from\: [LINK]
Complications
Source\: geekymedics.com
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