Investigation of Microvascular Involvement Through Nailfold Capillaroscopic Examination in Children with Familial Mediterranean Fever

<i>Background and Objectives:</i> Familial Mediterranean fever (FMF) is a lifelong autoinflammatory disease characterized by episodes of fever and aseptic polyserositis. Commonly associated with vasculitis, FMF's impact on microcirculation was investigated by examining nailfold capillaries using capillaroscopy. <i>Materials and Methods:</i> This study included 32 female and 28 male FMF patients diagnosed according to the Tel Hashomer and Yalçınkaya criteria and a control group of 20 female and 10 male age-matched cases. Demographic characteristics, medical history (abdominal pain, fever, chest pain, and joint pain), and physical examination findings of the cases were assessed. FMF gene mutations, acute-phase reactants, urine analysis, and spot urine protein/creatinine ratios were evaluated. Nailfold capillaries were examined via capillaroscopy by the same dermatology specialist. <i>Results:</i> There was no significant age or gender difference between groups. The most common symptoms in the case group were abdominal pain (81.7%) and joint pain (65%). Pathological findings in capillaroscopy, such as microhemorrhages and avascular areas, were significantly more frequent in the FMF case group (<i>p</i> < 0.001; <i>p</i> < 0.001). Physiological findings, including hairpin-shaped capillaries and shortened loops, were significantly more common in the control group (<i>p</i> = 0.001; <i>p</i> = 0.034). No significant relationships were found between kidney involvement, subclinical inflammation, presence of microhemorrhages and avascular areas in capillaroscopy, and disease duration. Additionally, no significant differences were observed in capillaroscopic findings between those with exon-10 mutations in the MEFV gene and those with non-exon-10 mutations. <i>Conclusions:</i> In conclusion, our study demonstrated secondary microvascular findings due to inflammation in FMF patients using capillaroscopy, a cost-effective and safe tool.