Mind the Gap atlas
Pityriasis rosea on Black skin
Key cue: Single 'herald patch' followed in 1-2 weeks by many smaller oval lesions in a Christmas-tree distribution on the trunk. On Black skin, lesions are hyperpigmented or violaceous rather than pink-salmon.
Pityriasis rosea is a self-limited eruption of unclear cause (likely HHV-6/7 reactivation), most common in adolescents and young adults. It resolves on its own in 6-8 weeks. The main reason to diagnose it is to reassure patients (and to rule out secondary syphilis, which can mimic it).
What it actually looks like
Textbook says
Textbook: a solitary 'herald patch' (2-5 cm, oval, salmon-pink with fine scale at the edges) appears on the trunk. 1-2 weeks later, numerous smaller oval papules and patches erupt along skin cleavage lines on the trunk, producing a Christmas-tree pattern on the back.
On Black skin
Two distinct features on Black skin:
- Lesions are hyperpigmented (dark brown), violaceous, or, less commonly, hypopigmented, not pink-salmon. The diagnostic feature is the inverse collarette scale, fine scale at the inner edge of the lesion, not the outer, which is pigment-independent and helps distinguish PR from tinea corporis (which has outer-edge scale).
- Inverse pityriasis rosea (in flexural/intertriginous areas rather than trunk) and papular / vesicular variants are more common on Black skin and can confuse the picture.
- Post-inflammatory hyperpigmentation after the eruption resolves can persist for weeks to months.
- Because pityriasis rosea and secondary syphilis can look similar (especially on Black skin), it is reasonable to check an RPR for any patient with a PR-like eruption who is sexually active. Secondary syphilis lesions can also involve palms and soles, a finding that is absent in PR.
What to look for
- A single larger oval patch, often on the trunk, preceding a wider rash by 1-2 weeks.
- Numerous smaller oval papules/plaques on the trunk, shoulders, upper arms, and thighs, following skin cleavage lines.
- Fine scale at the inner edge of each lesion.
- Mild itch in about half of patients.
- No palms/soles involvement (differentiator from syphilis).
When to seek care
Routine primary-care or dermatology visit to confirm the diagnosis and exclude mimics (syphilis, tinea, drug eruption). Treatment is supportive, oatmeal baths, moisturiser, antihistamines for itch. A short course of oral acyclovir within the first week may shorten duration.
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Find careCommon misdiagnosis
Pityriasis rosea on Black skin is frequently confused with tinea corporis (outer-edge scale, positive KOH), secondary syphilis (check RPR if sexually active, palms/soles involved), nummular eczema (more itchy, no herald patch), and drug eruption (history of new medication).
See it for yourself, curated external imagery
We don't host clinical photos here. The links below go to peer-reviewed or open-access sources (Mind the Gap, DermNet NZ, PubMed Central, and similar). Each opens in a new tab.
- DermNet NZ, Pityriasis rosea, image set including skin-of-colour examples.
- Mind the Gap handbook.
- Skin of Color Society, Pityriasis rosea.
References
- Drago F, Broccolo F, Rebora A. Pityriasis rosea: an update with a critical appraisal of its possible herpesviral etiology. J Am Acad Dermatol. 2009;61(2):303-18. PMID: 19615540.
- Jacyk WK. Pityriasis rosea in Nigerians. Int J Dermatol. 1980;19(7):397-9. PMID: 7419403.
Medical disclaimer
Educational content only. This is not a substitute for in-person evaluation. If you are worried about yourself or someone you love, see a clinician, and if you are concerned about an emergency sign described here, call 911 or your local emergency number. We do not host clinical imagery; the external references are for reader self-education and are not owned by or affiliated with Black Health.