Cutaneous lupus (cutaneous lupus erythematosus)

Cutaneous lupus erythematosus affects the skin and can occur alone or alongside systemic lupus. Research describes ultraviolet light as a key environmental trigger, setting off apoptosis in skin cells that exposes self-antigens and prompts native skin cells, along with innate and adaptive immune cells including Th1 and Th17 cells, cytotoxic T cells, and dendritic cells, to drive and sustain the inflammatory rash. Genetic and immunological factors also shape who develops the condition and which of its several forms, including discoid, subacute, and acute cutaneous lupus, they experience.

Cutaneous lupus is more evenly split between men and women than systemic lupus and tends to appear somewhat later in life, and research describes its overall incidence as roughly similar to that of systemic lupus, with a notably higher prevalence among Black patients in the studies reviewed.

Common signs

Depending on the form, round coin-shaped patches of thick, inflamed skin (discoid), ring-shaped or scaly rashes on sun-exposed areas, or a butterfly-shaped rash across the cheeks and nose (acute). Rashes often flare with sun exposure, may itch or sting, and discoid patches can leave scars, color changes, and permanent hair loss when they involve the scalp.

This is a plain-language summary for orientation, not a diagnosis. Mechanisms are described as current understanding, not settled fact. Work with your own clinician for your care.