Pityriasis Rosea Flashcards
Who does Pityriasis Rosea effect?
Young healthy individuals
10 - 35 year olds
* Peak incidence is during adolescence
No racial prediliction
Possible female predominance
How does Pityriasis Rosea present?
Solitary lesion appears on the trunk (herald patch)
- enlarges over several days
- pink, salmon, brown in colour
- can be a patch or a plaque
- fine scale in the centre
- margin has a trailing collarette of scale
Followed by
- widespread papulosquamous eruption on the trunk / limbs
- smaller thin papules and plaques
- round or oval in shape
- fine scale centrally, collarette of trailing scale peripherally
- subtle advancing border
- follicular accentuation
- follow the langer cleavage lines = christmas tree pattern
- +/- small pustules
Sparing of the face / palms or soles (typically)
Eruption generally lasts 6 - 8 weeks, rarely persisting for months
Can be proceeded by a viral prodrome
What is seen on histo of Pityriasis Rosea?
Spongiotic dermatitis
Elongation of the Rete Ridges
Enlargement of dermal papillae
Parakeratosis
Papillary dermal infiltrate of lymphocytes and histiocytes
Mild erythrocyte extravasation
What is the DDx for Pityriasis rosea?
Syphillus
Drug eruptions
Tinea corporis
Tinea veriscolour
Nummular dermatitis
Guttate psoriasis
PLC
How do you treat Pityriasis Rosea?
Reassurance if assymptomatic
Anti-puritic agents
- antihistamines
- Menthol 1% in aqueous cream
- low - medium dose TCS
NbUVB
Oral aciyclovir
Erythromycin
What causes Pityriasis rosea?
Unknown
Viral aeitiology is proposed
- HHV-7
- HHV-6
- HHV - 8
- h1n1
- influenza
- sars-cov-2
Is Pityriasis Rosea dangerous?
No - self limiting
However - in pregnant women there is a posisble association with spot. abortion (in the context of HHV-6 infection)
Describe the lesions
Red-brown plaques
Fien central scale
Peripheral collarette (training scale)
Describe
Widespread papulosquamous eruption
red-brown round / oval papules on the chest and abdomen
One larger plaque on the left breast (herald patch)
Fine scale
