Pityriasis Rosea
Pityriasis Rosea is a self-limiting, papulosquamous skin eruption, likely associated with reactivation of Human Herpesvirus 7 (HHV-7) or HHV-6.
Clinical Course
- Herald Patch: The initial finding: a solitary, large, salmon-colored, oval plaque with a collarette of scale.
- Generalized Eruption: Follows 1–2 weeks later; smaller, similar lesions are distributed along skin tension lines on the trunk, often described as a “Christmas Tree” pattern.
- Duration: Typically resolves spontaneously within 6–8 weeks.
Diagnostic & Management Pearls
| Key Concept | Details |
|---|---|
| Diagnosis | Clinical: No biopsy or serology required in classic cases. |
| Treatment | Reassurance; symptomatic treatment for pruritus (e.g., antihistamines or topical steroids). |
High-Yield Exam Pearl:
- Differential: A generalized scaling rash must always prompt a search for Secondary Syphilis. If a patient presents with a rash on the trunk and an “allergic” presentation, always check palms, soles, and history for a painless chancre.
- Herald Patch: Remember it is solitary and precedes the trunk-dominant rash by days to weeks.