Epidemiology
Etiology
Pathophysiology
Clinical features
- Prodrome (1–2 weeks prior to rash onset): flu-like symptoms (e.g., malaise, fever, pharyngitis)
- Initial eruption (∼ 90% of cases): herald patch (mother patch)
- Herald/mother = followed days later by other scaly erythematous plaques
- Single ovoid macule or patch, 2–10 cm in diameter
- Slightly raised, dark red border with a central salmon-colored clearing zone
- Surrounded by a collarette: a collar of fine, white scales (like cigarette paper)
- Typically on the back
- Secondary eruption (2–21 days later)
- Bilateral diffuse, oval-shaped, salmon-colored papules and plaques (< 1.5 cm) with scaly collarette
- Papules appear along Langer lines, which align on the back like the branches of a Christmas tree (Christmas tree appearance)
Diagnostics
Treatment