Ecthyma Gangrenosum Revealing X-Linked Agammaglobulinemia: A Case Report

Ecthyma gangrenosum (EG) is a rare, rapidly progressive necrotizing skin infection most commonly caused by Pseudomonas aeruginosa. It predominantly affects immunocompromised patients, particularly those with neutropenia or humoral immune deficiencies. We report the case of a 14-month-old male infant who presented with diffuse ulceronecrotic skin lesions leading to the diagnosis of X-linked agammaglobulinemia (Bruton disease). The diagnosis of ecthyma gangrenosum was confirmed by isolation of Pseudomonas aeruginosa from cutaneous samples. Management combining targeted dual intravenous antibiotic therapy and immunoglobulin replacement resulted in a favorable clinical outcome. This case highlights the importance of systematically investigating underlying primary immunodeficiency in infants presenting with severe or atypical ecthyma gangrenosum.