The patient was 68-year-old woman who had a history of bullous pemphigoid (BP), which had appeared more than 10 years earlier, and was being treated with prednisone (5 mg/d) since 2014. Fingernail involvement, with onycholysis and subungual hyperkeratosis, began in 2014, coinciding with a major flare-up. The patient reported no involvement of the feet. After repeated negative mycological cultures, the fingernail involvement was attributed to the underlying disease. Despite good control of BP the patient’s fingernail condition continues to persist in the form of onycholysis affecting several nails, marked longitudinal striation, and dorsal pterygium (Fig. 1).

Figure 1

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Nail involvement in BP is rare, although an increase in incidence has been reported in recent years. A potential etiological and pathogenic role has been attributed to anti-BP antigens expressed in the nail matrix, the proximal nail fold, the nail bed, and the hyponychium, and to the formation of periungual blisters. Nail manifestations reported to date include onychomadesis, paronychia, onycholysis, and loss of the entire nail. Dorsal pterygium has been described in cicatricial pemphigoid.

Pterygium appears as a consequence of nail matrix involvement and scar tissue formation. Common causes include trauma and various inflammatory processes such as lichen planus and graft-versus-host disease. Its association with BP is rare.