Pityriasis rosea
Definition & Epidemiology
- Pityriasis rosea (PR, Gibert disease) = acute, self-limiting exanthematous dermatosis probably triggered by HHV-6 / HHV-7 reactivation (Drago 2005).
- Epidemiology: Peak incidence 10–35 years, F: M ≈ 1.5: 1 with seasonal clustering in spring and autumn.
- Incidence: approx. 170 / 100,000 / year.
Pathogenesis
- HHV-6/-7 reactivation with viral DNA detectable in plasma and skin lesions; systemic viral replication with cutaneous manifestation.
- Triggers / Mimics: Frequently viral respiratory infection + stress + vaccinations (COVID, MMR).
- PR-like Drug Eruption: Captopril, beta-blockers, NSAIDs, imatinib, anti-PD-1 — important to distinguish due to longer persistence and pruritus.
Clinical Presentation
- Herald patch (Tâche mère): oval erythematous-scaly plaque 2–5 cm with collarette scaling on trunk / proximal extremities, 1–2 weeks before exanthem.
- Secondary efflorescences: smaller oval plaques along Langer's cleavage lines → classic "Christmas tree pattern" on back.
- Special locations: Atypical PR variants include inverse (axilla / groin) + papular (children) + vesicular + purpuric.
- Symptoms: mildly pruritic (in 50 %), occasionally prodromal symptoms (fatigue, cephalgia, pharyngitis).
- Course: Spontaneous healing in 6–8 weeks with rare recurrences.
Diagnostics
- Clinical visual diagnosis — herald patch + Christmas tree pattern is pathognomonic.
- Laboratory / tests: Obligatory exclusion in sexually active adults is TPHA / RPR (secondary syphilis) — secondary syphilis can be very PR-like, but with palmoplantar involvement + lymphadenopathy!
- KOH preparation to exclude tinea corporis with isolated plaques.
- Skin biopsy only in atypical courses → superficial perivascular lymphocytic infiltrate, spongiosis, parakeratotic scale.
Differential diagnoses
- Atopic dermatitis (atopic eczema)
- Secondary syphilis (lues II)
- Tinea corporis
- Pityriasis versicolor
- Lichen planus
- Psoriasis vulgaris (plaque psoriasis)
- Pityriasis lichenoides chronica (PLC)
- PLEVA (Pityriasis lichenoides et varioliformis acuta)
Practise Pityriasis rosea in the app
Flashcards with spaced repetition, exam questions and spot-the-diagnosis on this topic – in DermaFuchs, free of charge.
In the DermaFuchs app: 6 flashcards · 12 clinical images
Open in browser Download on the App StoreSources (selection)
More inflammatory skin diseases
- Cheilitis granulomatosa (Miescher)
- Erythema annulare centrifugum (EAC)
- Erythema nodosum
- Graft-versus-host disease (GvHD)
- Granuloma annulare
- Cutaneous sarcoidosis
- Lichen planus
- Lichen sclerosus
Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases. Treatment and follow-up content is available in the app.