Background: The febrile episodes of periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome occur, by definition, every 2 to 8 weeks.

However, a subset of our patients appears to experience attacks at an even higher rate of more than twice a month, and was therefore named extreme PFAPA, or ePFAPA group.

Objectives: To characterize this group both demographically and clinically in order to compare them to the non-extreme PFAPA (nPFAPA) group.

Methods: We retrospectively reviewed the medical records of patients with PFAPA that were treated in the Schneider Children’s Medical Center of Israel from 3/2014 to 4/2021. Patients with concomitant familial Mediterranean fever were excluded. Thereafter the ePFAPA and nPFAPA groups were compared using Wilcoxon rank sum, Pearson’s chi-squared and Fisher’s exact tests.

Results: 47 patients (12.9%) out a total of 365 PFAPA patients were included in the ePFAPA group. Compared to the nPFAPA group, ePFAPA patients had earlier disease onset (age 1.7 vs 2.96 years, P<0.001) and diagnosis (age 2.94 vs 5.02 years, P<0.001). Moreover, after initiation of an abortive treatment with corticosteroids, ePFAPA patients had higher increased flares frequency (72% vs 40%, P<0.001) and were treated with colchicine prophylaxis more often (67% vs 26%, P<0.001). Other clinical and demographic aspects were not significantly different between the two groups.

Conclusion: EPFAPA patients are a subset of patients who have earlier onset and diagnosis of PFAPA, and also increased flares frequently after abortive therapy with steroids. Current study is underway to describe the long-term outcome of this group.

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Disclosure of Interests: None declared