Not easy-peasy to diagnose: familial Mediterranean fever unaccompanied by fever as neither always Mediterranean

Abstract

Abstract Purpose Classical attacks of familial Mediterranean fever (FMF) are often accompanied by fever, but some of the patients have attacks without fever. This study aimed to compare the characteristics of FMF patients with and without fever during their attacks and draw attention to the different clinical presentations of FMF in children.Methods Medical files of patients aged 0–18 years who were followed up with the diagnosis of FMF in two reference pediatric rheumatology centers were reviewed retrospectively. The patients were divided into two groups: Children who had had no fever in any of their attacks were assigned as group 1, and those who had fever during their attacks were classified as group 2.Results Out of 2003 patients evaluated, 191 (9.53%) patients had attacks not accompanied by fever and their median age at onset of symptoms (7.0 vs. 4.0 years, p < 0.001) and the median age at diagnosis (8.6 vs. 6.0 years, p < 0.001) were significantly higher, however group 2 had delay in diagnosis. The annual number of attacks and abdominal attacks were more common in group 2, arthritis, arthralgia, erysipelas-like rash, exercise-induced leg pain, and myalgia were more common in group 1.Conclusion The data from the assessment of children with FMF attacks not accompanied with fever were presented for the first time. Children with late age onset of FMF and dominance of musculoskeletal features may display attacks not accompanied with fever.