Sciogliere i nodi della diagnosi: l'identità di una panmiculite

Panniculitis is an inflammation of the subcutaneous adipose tissue. While often idiopathic or associated with erythema nodosum, it necessitates a thorough investigation into underlying causes—such as infectious, systemic, drug-related, or neoplastic/oncological factors. We describe the case of a 13-year-old boy presenting with fever, abdominal pain, and painful erythematous plaques on his lower limbs, which proved refractory to antibiotic therapy and NSAIDs. Although an abdominal CT scan and autoimmune and microbiological screenings were negative, laboratory tests revealed elevated inflammatory markers, high calprotectin levels, and a marked increase in anti-streptococcal antibody titers (ASO and anti-DNase B). A skin biopsy proved definitive, confirming a diagnosis of post-streptococcal panniculitis. This case underscores the critical role of skin biopsy in the diagnosis of atypical or refractory paediatric panniculitis.