Pityriasis rosea Flashcards
A patient has a puritic rash that looks like this, what is the likely diagnosis?
Pityriasis rosea.
**Differential diagnosis: **
Tinea corporis
Pityriasis versicolor
Drug eruptions
Psoriasis
Lichen planus
Secondary syphilis
What is the typical onset of Pityriasis rosea?
It often starts with a herald patch (a single, oval macule) followed by a secondary eruption of multiple papules with a characteristic Christmas tree pattern.
What is the suspected cause of Pityriasis rosea?
A viral etiology is suspected
specifically Human Herpesvirus 6 and 7
(HHV-6 and HHV-7; roseola or “exanthema subitum”).
What are the typical clinical features of Pityriasis rosea?
It begins with a flu-like prodrome (fever, malaise), followed by a herald patch (1-5 cm) with a dark red border and salmon-colored clearing in the center, surrounded by a fine, ring-like collarette of scales.
What is the usual distribution of Pityriasis rosea lesions?
The rash typically occurs on the trunk, neck, and upper extremities, with more severe cases involving the scalp and face, especially in individuals with dark skin.
What is the treatment for Pityriasis rosea?
Treatment is usually symptomatic, including emollients, topical corticosteroids, oral antihistamines for pruritus, and acyclovir for persistent, severe, or pregnancy cases. This is an important clinical point because this occurs more frequently in the pregnant patient population and can lead to complications (e.g., preterm birth, stillbirth, spontaneous abortion).
Severe disease may benefit from UVB therapy.
How long does Pityriasis rosea usually last?
Lesions usually resolve on their own within 6-12 weeks.
What is the main differential diagnosis for Pityriasis rosea?
The main differential diagnoses include tinea corporis, psoriasis, lichen planus, and secondary syphilis.
Why is Pityriasis rosea more common in certain populations?
It is more common in young adults (ages 10-35), and pregnant women are at higher risk for more severe symptoms and complications such as preterm birth or stillbirth.
What is the management for Pityriasis rosea during pregnancy?
In pregnancy, it can manifest with more severe symptoms. Specialist consultation is recommended, and acyclovir can be used off-label, with maternal-fetal medicine referral for complications.
What is the relapse rate for Pityriasis rosea?
Relapse is rare, but it typically occurs within 5-18 months.
