Localized Discoid Lupus Erythematosus of the Auricular Concha: A Case Report Highlighting the Diagnostic Relevance of the Carpet Tack Sign.

Discoid lupus erythematosus is a chronic autoimmune inflammatory dermatosis characterized by erythematous, scaly plaques that may progress to permanent atrophy, scarring, and pigmentary alterations. The auricle is a recognized site of involvement in discoid lupus erythematosus; however, isolated lesions confined to the auricular conchae are less frequently described and may pose diagnostic challenges because of their clinical resemblance to other inflammatory, infectious, or neoplastic conditions of the ear. We report the case of a 35-year-old woman with a 15-year history of asymptomatic bilateral lesions involving the auricular conchae. Physical examination revealed violaceous, poorly defined oval plaques with thick, adherent whitish scale, accompanied by multiple whitish filiform papules consistent with the carpet tack sign. Dermoscopic evaluation demonstrated a violaceous-brown plaque with thick adherent scale, multiple whitish punctate projections, and perifollicular whitish halos. Histopathological examination showed epidermal atrophy, prominent follicular plugging, interface dermatitis with apoptotic keratinocytes, dermal melanophages, thickening of the basal membrane, and increased interstitial mucin, findings consistent with discoid lupus erythematosus. This case highlights the diagnostic value of recognizing characteristic clinical and dermoscopic features, particularly the carpet tack sign, in localized auricular disease. Early identification enables timely diagnosis and appropriate management, thereby helping to prevent irreversible scarring and long-term sequelae in this anatomically and aesthetically sensitive area.