Subacute cutaneous lupus erythematosus

Subacute cutaneous lupus erythematosus (SCLE) is a specific subset of cutaneous lupus erythematosus characterized by widespread, photosensitive, non-scarring skin lesions. It primarily affects the skin, though some patients may develop mild systemic manifestations. SCLE accounts for approximately 10-15% of all lupus erythematosus cases and predominantly affects women. The condition presents with two main morphological patterns: annular/polycyclic lesions with raised red borders and central clearing, or papulosquamous (psoriasiform) lesions that resemble psoriasis. These lesions typically appear on sun-exposed areas such as the upper back, shoulders, extensor surfaces of the arms, neck, and upper chest, while the face is relatively spared compared to other forms of lupus. The lesions heal without scarring but may leave long-lasting depigmentation or hyperpigmentation. SCLE is strongly associated with anti-Ro/SSA antibodies, which are found in approximately 70-90% of affected individuals. Anti-La/SSB antibodies are also frequently present. The condition has a notable association with HLA-DR3 and HLA-B8 haplotypes. Importantly, SCLE can be drug-induced in a significant proportion of cases, with common culprits including hydrochlorothiazide, terbinafine, calcium channel blockers, ACE inhibitors, proton pump inhibitors, and TNF-alpha inhibitors. While most patients with SCLE have a relatively benign course compared to systemic lupus erythematosus (SLE), approximately 10-15% may meet criteria for SLE, and patients should be monitored for systemic involvement including arthralgia, fatigue, and mild renal or hematologic abnormalities. Treatment of SCLE centers on strict sun protection and avoidance of photosensitizing triggers. First-line pharmacological therapy includes topical corticosteroids and antimalarial agents, particularly hydroxychloroquine. For refractory cases, additional immunosuppressive or immunomodulatory agents such as methotrexate, mycophenolate mofetil, dapsone, or thalidomide may be considered. In drug-induced SCLE, discontinuation of the offending medication is essential and often leads to resolution of skin lesions, though this may take weeks to months. Smoking cessation is also recommended, as tobacco use can reduce the efficacy of antimalarial therapy.

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