Atypical Lower Extremity Discoid Lupus Erythematosus Associated With Newly Diagnosed Systemic Lupus Erythematosus in a Male Patient: A Case Report.

Discoid lupus erythematosus (DLE) classically affects sun‑exposed areas, such as the face, scalp, and ears. Involvement of the lower extremities is uncommon, and presentation of DLE in association with systemic lupus erythematosus (SLE) in a male patient is relatively rare. This case report describes a 34‑year‑old man who presented with chronic, scaly, dyspigmented plaques confined to both the lower legs, which prompted further evaluation and led to the diagnosis of SLE. Histopathological evaluation supported the diagnosis of DLE, while serologic workup revealed high‑titer antinuclear antibodies (ANAs), anti‑double‑stranded DNA (anti‑dsDNA), anti‑Smith antibodies, and hypocomplementemia, supporting a diagnosis of SLE with chronic cutaneous lupus involvement. Following treatment with strict photoprotection, topical corticosteroids, and weight‑based hydroxychloroquine, the patient showed marked clinical and serologic improvement at the 12‑week and 9‑month follow‑ups. This case highlights the importance of evaluating for systemic involvement in patients with biopsy‑supported DLE, particularly when lesions occur in atypical anatomical locations and in populations traditionally considered at lower risk.