Pityriasis Rosea Flashcards
What is pityriasis rosea (PR)?
A self-limiting, acute, inflammatory skin disorder characterized by a distinctive rash, often starting with a “herald patch” followed by a widespread eruption of smaller lesions.
What is the typical course of pityriasis rosea?
The condition resolves spontaneously within 6–8 weeks.
Who is most commonly affected by pityriasis rosea?
Adolescents and young adults (10–35 years).
Slightly more common in females.
What is the suspected cause of pityriasis rosea?
Believed to be associated with reactivation of human herpesvirus 6 (HHV-6) or human herpesvirus 7 (HHV-7).
Are there any known triggers for PR?
Viral infections, stress, and certain medications (e.g., ACE inhibitors, NSAIDs) have been implicated in triggering PR-like eruptions.
What is the hallmark initial lesion in pityriasis rosea?
The herald patch: A single, oval, pink or salmon-colored plaque with a fine, collarette scale along the border.
How does the rash evolve after the herald patch?
Within 1–2 weeks, smaller oval lesions develop along Langer’s lines (cleavage lines of the skin), forming a “Christmas tree” distribution on the trunk.
What are the key characteristics of PR lesions?
Oval, salmon-colored plaques.
Fine, peripheral collarette of scale.
Often concentrated on the trunk and proximal limbs.
Are there systemic symptoms associated with PR?
Some patients may report mild prodromal symptoms like fatigue, headache, or low-grade fever before the rash appears.
What are the atypical variants of pityriasis rosea?
Inverse PR: Lesions concentrated in intertriginous areas (e.g., axillae, groin).
Papular PR: Common in darker-skinned individuals, presenting with raised, papular lesions.
Vesicular PR: Rare, with small blisters.
PR in pregnancy: Can be more severe and associated with adverse outcomes in rare cases.
How is pityriasis rosea diagnosed?
Clinical diagnosis: Based on characteristic rash and distribution.
Rule out differential diagnoses: Secondary syphilis, tinea corporis, and drug eruptions.
Laboratory tests: Not routinely needed, but rapid plasma reagin (RPR) or VDRL may be done to rule out syphilis if the presentation is atypical.
What is the main treatment for pityriasis rosea?
No specific treatment is required; it is self-limiting and resolves in 6–8 weeks.
What symptomatic treatments are available for PR?
Antihistamines: For pruritus.
Topical corticosteroids: Low- to mid-potency for itching or irritation.
Emollients: To soothe dry skin.
What is the role of antiviral therapy in PR?
In severe or prolonged cases, acyclovir may be considered, though its efficacy is uncertain.
How can phototherapy be used in PR?
Narrowband UVB therapy may help reduce symptoms in persistent or severe cases.
