Overview
Classify acute, subacute and chronic cutaneous lupus, detect systemic organ involvement, prevent ultraviolet and scarring damage, and use local or antimalarial treatment with reproductive and retinal safeguards.
Cutaneous lupus erythematosus is a spectrum of interface dermatitis classified by morphology, duration, scarring and systemic association. Acute disease is closely linked to systemic activity. Subacute disease is highly photosensitive and often anti-Ro positive, with a meaningful drug-induced subgroup. Chronic discoid disease may remain cutaneous but creates irreversible scarring and dyspigmentation, especially on scalp and conchal ears. A person can have more than one subtype, and the skin label does not determine whether kidney, blood or neurological disease is present.
Ultraviolet exposure modifies keratinocyte antigens and immune signalling, which helps explain delayed flares after light exposure and the need for high-UVA protection even through windows. Smoking is associated with worse cutaneous activity and reduced antimalarial response. Hydrochlorothiazide, terbinafine, proton-pump inhibitors and other medicines can trigger an SCLE phenotype, but medication changes require prescriber coordination and an assessment of latency rather than reflex withdrawal.