Acrodermatitis continua of Hallopeau-clinical review and proposed management algorithm.

Acrodermatitis continua of Hallopeau (ACH) is a rare inflammatory condition primarily affecting the fingers. It is characterized by painful paronychia with sterile pustules on an erythematous base around the nail folds and in the nail bed, which can progress to nail deformation and atrophy. In severe cases, resorptive osteolysis is a possible sequela. ACH is characterized by an inflammatory response resulting from innate immunity hyperactivation. Genetic mutations play a significant role in its pathogenesis, with the IL-36RN gene (mutated in 20% of cases) most often implicated. Treatment of ACH is challenging, with a low response to therapies. Systemic treatment is generally preferred, even in cases with localized presentation, and topical medications are considered only supportive. Acitretin is recommended as first-line treatment, although the disease often relapses, necessitating a more targeted therapeutic approach. Biologic drugs show good efficacy, but even these do not provide long-lasting remission. Despite emerging therapeutic options, ACH remains difficult to treat, and further research is needed to identify more effective strategies, including molecular profiling of the inflammatory infiltrate for a more personalized treatment.