Exclusive lingual psoriasis revealed by dermoscopy

Psoriasis is a chronic immune-mediated disease, in which oral involvement is uncommon and frequently overlooked. We report a 38-year-old man with no personal or family history of psoriasis who presented with chronic, recurrent erythematous depapillation of the left hemi-tongue, and unresponsive to prolonged antifungal therapy. Dermoscopy showed regularly distributed dotted vessels over hypertrophic papillae, contrasting with the normal contralateral mucosa, and guided a targeted punch biopsy. Histology demonstrated psoriasiform epithelial hyperplasia with parakeratosis, elongated rete ridges, and dilated tortuous capillaries within the lamina propria and Munro microabscesses; periodic acid-Schiff staining excluded fungal infection. Extension work-up disclosed no cutaneous, scalp, nail, or joint involvement, supporting exclusive lingual psoriasis. Topical clobetasol propionate produced marked improvement within 4 weeks, with no relapse after 1 year of follow-up. This case illustrates the value of dermoscopy in recognizing atypical oral psoriasis and in avoiding prolonged ineffective antifungal treatment.