An Uncommon Presentation of Tumid Lupus Erythematosus Manifesting As Annular, Non-scarring Alopecia on the Scalp.

Tumid lupus erythematosus (TLE) is a rare subtype of cutaneous lupus, which can present diagnostic challenges due to its overlapping features with other skin disorders. Understanding the clinical and histopathological characteristics of TLE is essential for accurate diagnosis and management. In this article, we describe a case of TLE in a 45-year-old man who presented with annular, urticarial, non-scarring plaques on the scalp associated with non-scarring alopecia in the affected area. The patient had a long history of scalp lesions with intermittent resolution and no associated systemic symptoms. On examination, the patient had erythematous, edematous, non-scaly plaques on the occipital and temporal scalp regions, and hair loss was observed in these areas, consistent with non-scarring alopecia. Dermoscopy revealed arborizing blood vessels on a background of erythema, with no scaling, atrophy, or follicular plugging. A skin biopsy confirmed the diagnosis, revealing the characteristic periadnexal and perivascular lymphocytic infiltrates with dermal mucin and edema. Laboratory tests showed a decreased C4 complement level, though other autoimmune markers were within normal limits. The patient showed no systemic symptoms or other signs of systemic lupus erythematosus (SLE). The patient was treated with topical clobetasol dipropionate 0.05% ointment, which resulted in rapid improvement of the lesions. This case underscores the need to include TLE in the differential diagnosis when evaluating annular scalp lesions with associated non-scarring alopecia and emphasizes the critical role of histopathological examination in confirming the diagnosis.