[Acrodermatitis continua of Hallopeau and psoriatic arthritis: A case report].

A 44-year-old man, previously healthy, consulted for a three-month history of asymmetrical polyarthralgia with inflammatory features involving small and large joints. A few days later, he developed erythema covered by pustules in the nail folds and progressive degeneration of the nail plate of the left thumb, with severe functional limitation. The physical exam showed well-defined erythematous scaly and pustular plaques in the first and third fingers of the left hand, with severe onychodystrophy, which was a key aspect in the diagnosis of acrodermatitis continua of Hallopeau. Other signs of the psoriatic spectrum were observed: erythematous patches of the scrotum, erythematous scaly plaques with hemorrhagic crusts on both knees, and dactylitis. The diagnosis of inverse psoriasis, plaque psoriasis, and pustular psoriasis, respectively, were confirmed by histopathology and, with the CASPAR criteria, psoriatic arthritis. This case is of particular dermatological interest due to the variety of psoriatic manifestations recognized in a single patient and because of the poorly described association between acrodermatitis continua of Hallopeau with psoriatic arthritis.