Exploring the significance of vitamin D insufficiency in the periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome: a single-center retrospective assessment during the decade 2014-2024.

The underlying mechanisms responsible for the periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome are unknown. The main purpose of this study was to retrospectively assess different characteristics and lab-work investigations including serum 25(OH)-vitamin D levels in patients with PFAPA syndrome evaluated at our University hospital during the decade 2014-2024. The medical charts of 151 children with diagnosis of PFAPA syndrome were retrospectively evaluated: for each patient demographic data, clinical manifestations during acute episodes, and laboratory analyses during a well-being phase within the trimester following PFAPA diagnosis were examined. A focus was given to serum 25-hydroxyvitamin D [25(OH)-vitamin D] concentration, recognized as the functional status indicator for vitamin D. Based on the reference values for normal serum 25(OH)-vitamin D, patients were divided into two groups (inadequate versus normal vitamin D levels); the groups were compared to identify if hypovitaminosis D could have any relationship with the evolution of PFAPA syndrome over time. Forty-five PFAPA patients (30% of the whole cohort) had serum 25(OH)-vitamin D below the normal reference (< 30 ng/mL), and inadequate vitamin D serum levels were associated with a persistent pattern of PFAPA syndrome, also showing an inverse correlation with age at disease onset. This study offers a static snapshot of vitamin D status in children with PFAPA syndrome, without accounting for specific time points, and suggests that serum 25(OH)-vitamin D levels might contribute to a longer duration of the recurring PFAPA symptoms.