Discoid Lupus Erythematosus in Genital Skin: A Case Report and Review of the Literature.

BACKGROUND: Discoid lupus erythematosus (DLE) represents the most common variant of chronic cutaneous lupus erythematosus, a skin-specific autoimmune disorder within the broader lupus erythematosus spectrum Clinically, DLE is characterized by erythematous, scaly plaques with areas of hyperpigmentation. These lesions predominantly occur on sun-exposed areas, particularly the scalp and cheeks. Involvement of the genital skin is rare and poses a significant diagnostic challenge due to its clinical overlap with other inflammatory and infectious dermatoses. To date, only 14 cases involving genital skin have been documented in the literature, with most described in female patients and a particular tendency for the vulva to be affected.

CASE PRESENTATION: We present the case of a 60-year-old female with a past medical history of systemic sclerosis and Raynaud's syndrome, who presented with well-demarcated, erythematous, keratotic plaques with atrophy involving the inguinal creases and medial buttocks, associated with pruritus and recent onset of pain when sitting. The rash had been present for years. Clinical differential diagnoses included lichen sclerosus, lichen simplex chronicus, and psoriasis. Histopathologic examination revealed orthokeratosis and parakeratosis, epidermal hyperplasia, thickened basement membrane, dilated blood vessels, and perivascular inflammation. Plasmacytoid dendritic cells were present in the dermis and highlighted by CD123 immunohistochemical stain, supporting the diagnosis of DLE. Systemic evaluation was negative for systemic lupus erythematosus. The patient was started on treatment with topical corticosteroids.

CONCLUSION: This case highlights the importance of including DLE in the differential diagnosis of chronic genital dermatoses and reinforces the value of histopathologic evaluation in such cases.