Exploring factors for predicting colchicine responsiveness in children with PFAPA.

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis syndrome (PFAPA) are the most common autoinflammatory syndromes in children. This study aimed to evaluate the clinical and laboratory parameters that may predict colchicine responsiveness.This retrospective, multicenter, cross-sectional study involved nine pediatric rheumatology centers from our country., The patients diagnosed with PFAPA were compared on the basis of their responses to colchicine. In the 806 (42.3% female 57.7% male) patients, the most common clinical findings were fever (100%), exudative tonsillitis (86.5%), pharyngitis (80.9%), and aphthous stomatitis (50.5%). The mean attack frequency was 13.5 ± 6.8 attacks per year lasting for a mean of 3.9 ± 1.1 days. Colchicine treatment was attempted in 519 (64.4%) patients, with 419 (80.7%) showing a favorable response. In patients who underwent MEFV gene analysis (70.8%), the most common variant was M694V heterozygous (16.8%). The presence of pharyngitis (p = 0.03, 95% CI 0.885 to 0.994), the presence of arthralgia (p = 0.04, 95% CI 0.169 to 0.958), and having more frequent attacks (p = 0.001, 95% CI 0.028 to 0.748) were found to be associated with colchicine unresponsiveness, whereas the carriage of the M694V variant (p = 0.001, 95% CI 0.065 to 0.242) was associated with colchicine responsiveness. CONCLUSION: This study identified the presence of pharyngitis, arthralgia, and increased attack frequency in patients with PFAPA as factors predicting colchicine unresponsiveness, whereas the carriage of the M694V variant emerged as a predictor of colchicine responsiveness. Predicting colchicine response at disease onset may facilitate a more effective management of PFAPA. WHAT IS KNOWN: • Colchicine treatment can be used in the prophylaxis of PFAPA disease. • Having the MEFV variant is the most commonly known factor in predicting response to colchicine. WHAT IS NEW: • The presence of pharyngitis or arthralgia, and more frequent attacks in PFAPA disease were found to be independently associated with colchicine unresponsiveness. • Carrying the M694V variant was identified as the sole factor predicting colchicine responsiveness.