Colchicine treatment in PFAPA: how long should we wait for the clinical response?

We aimed to evaluate the efficacy of prophylactic colchicine treatment in periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) using the Auto-Inflammatory Diseases Activity Index (AIDAI) score measured before and during treatment. We also aimed to determine the optimal treatment duration for observing clinical response and to identify factors predicting response to treatment. Children with PFAPA receiving colchicine were included in the study. We utilized AIDAI scoring system by evaluating the sore throat, tonsillitis, and oral aphthae under the general symptoms heading. This form of AIDAI was given to the families, and they were asked to document their symptoms on a daily basis. AIDAI scores were calculated for the month before colchicine initiation and for the first and third months after. Data were obtained retrospectively. The mean age of patients was 4.4 ± 2.13 years, and almost two third of them (50/76) were male. The difference in AIDAI scores between the month before colchicine treatment and the 1st month after the treatment was significant, while the difference between the 1st and 3rd month after the treatment was not (p = 0.002 vs. p = 0.463). Patient treatment responses were: 44 (57.9%) complete response, 15 (19.7%) partial response, and 17 (22.4%) unresponsive to colchicine.

Based on this finding, we can conclude that in the case of partial response to colchicine treatment after the first month, dose escalation, review of treatment compliance and the need for prophylaxis should be reevaluated.

• Colchicine prophylaxis is recommended in PFAPA patients; however, the optimal time point for response assessment remains unclear. • The AIDAI score is suggested for measuring disease activity in autoinflammatory conditions.

• This is the first repeated-measure study evaluating colchicine response in PFAPA patients using the AIDAI score. • Clinical response predominantly emerged within the first month, suggesting this period may be critical for evaluation.