Clinical implications of Vasculitis associated with familial Mediterranean fever: a comparative study in childhood

Familial Mediterranean Fever (FMF) is characterized by recurrent fever and serositis. Although not classical in FMF, vasculitis is increasingly reported, suggesting shared pathogenic mechanisms. This study aimed to evaluate clinical features and treatment responses in paediatric FMF patients with concomitant vasculitis.

The records of 1598 paediatric FMF patients followed at a tertiary paediatric rheumatology centre were reviewed retrospectively. After exclusions, 1481 patients were included: 1434 without vasculitis (Group 1) and 47 with vasculitis (Group 2). Demographic, clinical, genetic, and treatment-related data were compared between the groups, and vasculitis subtypes were characterized in detail.

Vasculitis was found in 3.2% of patients, most commonly IgA vasculitis and Behçet's disease. Group 2 had higher attack rates, more chest pain/myalgia, and more non-exon 10 heterozygous Mutations in the Mediterranean Fever mutations. Colchicine response and biologic therapy requirement did not differ significantly between groups. There was no statistically significant difference between groups in colchicine response (97.3 versus 74.5%) or biologic therapy requirement (2.7 versus 6.4%).

The coexistence of vasculitis in FMF likely reflects shared inflammatory mechanisms rather than coincidence. Vasculitis occurred even in patients with milder Mutations in the Mediterranean Fever genotypes, suggesting an enhanced proinflammatory milieu. Early recognition of vasculitis in FMF may influence therapeutic strategies and improve outcomes.