Refractory Acrodermatitis Continua of Hallopeau in a Pediatric Patient: Unveiling Underlying Mixed Connective Tissue Disorder.

Acrodermatitis continua of Hallopeau (ACH) is a rare pustular psoriasis variant that presents as sterile pustules on the hands and feet with a relapsing course. This condition is not easily treated, but literature shows some cases are successfully controlled with biologics such as etanercept, adalimumab, secukinumab, and ustekinumab. Mixed connective tissue disease (MCTD) is a type of autoimmune disease and is rarely seen in the pediatric population. It is characterized by overlapping features of various autoimmune disorders, often involving scleroderma, systemic lupus erythematosus, polymyositis, and other organ dysfunction. MCTD is typically diagnosed with lab testing to indicate the presence of specific autoantibodies to a nuclear matrix protein, such as ribonucleoprotein. This communication emphasizes the importance of revisiting diagnoses in patients with persistent, refractory skin conditions and highlights the need for comprehensive evaluation in the presence of evolving or atypical presentations, especially when autoimmune diseases are suspected. Steps for diagnostic workup and treatment may provide clinical benefits to patients and serve as a reference for other clinicians. The course of treatment for ACH and MCTD in the pediatric and adolescent population is discussed.