Enthesitis may be one of the signs of severe disease in familial Mediterranean fever.

Enthesitis may be a sign of more severe FMF phenotype and frequently associated with other musculoskeletal manifestations resemble SpA. Key points •More than one-fifth of the patients with FMF would suffer from enthesitis. •The FMF patients with enthesitis had higher ISSF scores; higher frequency of fever, exertional leg pain, myalgia and arthritis; and more intense, widespread, frequent and longer attacks as compared with controls. •Enthesitis may be a sign of more severe FMF phenotype and frequently associated with other SpA-like musculoskeletal feature.