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Cutaneous lupus erythematosus
Cutaneous lupus has three main forms — acute, subacute (SCLE) and chronic (discoid) — that differ in systemic risk, scarring and antibodies; all are photosensitive and are treated with sun protection and hydroxychloroquine.
Why it matters in the exam
Exam stems show scaly plaques on the face and ears that leave scars, depigmentation and hair loss — discoid lupus — or annular plaques on the upper trunk and arms in a woman with Ro antibodies, sometimes after starting a drug such as terbinafine, a proton-pump inhibitor or hydrochlorothiazide — SCLE. Asked are the risk of progression to systemic SLE (low in localised discoid, moderate in SCLE), neonatal lupus with complete heart block in a baby of a Ro-positive mother, and the effect of smoking, which reduces hydroxychloroquine efficacy. Remember also the distinction between the acute butterfly rash, which spares the nasolabial folds, and rosacea and dermatomyositis, and the need for periodic eye checks on hydroxychloroquine. Recognising the skin form matters because it decides which systemic tests to do and how closely to follow up. Basic tests include a blood count, urinalysis and antibodies.
Key points
- Cutaneous lupus is divided into acute, subacute and chronic forms, and each carries a different risk of systemic disease and scarring.
- The acute butterfly rash spares the nasolabial folds and usually indicates active SLE, but leaves no scar.
- SCLE presents with annular plaques on the upper trunk, is linked to Ro antibodies and can be caused by drugs such as terbinafine and thiazides.
- DLE leaves scars, depigmentation and scarring alopecia, and its risk of progression to SLE is low when localised.
- Treatment includes sun protection, stopping smoking, topical therapy and hydroxychloroquine with periodic eye checks.
Summary table
| Form | Appearance | Antibodies and systemic risk | Scarring and notes |
|---|---|---|---|
| Acute cutaneous lupus (ACLE) | Butterfly rash on the cheeks and nose, sparing the nasolabial folds | ANA, anti-dsDNA; almost always part of active SLE | No scarring; worsens in the sun |
| Subacute cutaneous lupus (SCLE) | Annular or papulosquamous plaques on the upper trunk and arms | Ro/SSA antibodies; about half meet SLE criteria, usually mild | No scarring; look for a triggering drug |
| Discoid lupus (DLE) | Plaques with adherent scale and follicular plugs on the face, ears and scalp | Low risk of progression to SLE when localised | Scarring, depigmentation and scarring alopecia |
| Neonatal lupus | Annular periorbital rash in a baby | Maternal Ro antibodies | Irreversible complete heart block; fetal heart monitoring |
| Lupus panniculitis | Deep nodules on the arms and face that leave depressions | Variable | Important to distinguish from subcutaneous lymphoma |
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Sources
- EULAR recommendations for the management of systemic lupus erythematosus, 2023 — Skin disease
- S2K guideline on cutaneous lupus erythematosus (EDF/EADV), 2017 — Classification and treatment
- British Association of Dermatologists guideline on cutaneous lupus, 2021 — Antimalarials and photoprotection
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.