Vitamin D levels and effects of vitamin D replacement in children with Periodic Fever, Aphthous stomatitis, Pharyngitis, and cervical Adenitis (PFAPA) syndrome

BACKGROUND: The periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA) syndrome is an autoinflammatory disease characterized by regularly recurrent fever episodes due to seemingly unprovoked inflammation. OBJECTIVE: To assess serum 25-hydroxyvitamin D [25(OH)D] concentrations in children with PFAPA syndrome and evaluate longitudinally the effect of wintertime vitamin D supplementation on the disease course. STUDY DESIGN: We have evaluated 25 Italian patients (19 males, 6 females, aged 2.4-5.3 years), fulfilling the Euro-Fever PFAPA criteria. For each patient, we recorded demographic and anthropometric data, clinical manifestations, serum calcium, phosphate, and 25(OH)D. After 400 IU vitamin D supplementation during wintertime, clinical and auxological characteristics, calcium, phosphate, and 25(OH)D levels were re-evaluated. Data were compared with a sex- and age-matched control group. RESULTS: PFAPA patients showed reduced 25(OH)D levels than controls (p<0.0001). Regarding the effect of seasons on vitamin D, winter 25(OH)D levels were significantly reduced than summer ones (p<0.005). Moreover, these levels were significantly lower than in healthy controls (p<0.005), and correlated with both fever episodes (p<0.005) and C-reactive protein values (p<0.005). After vitamin D supplementation, PFAPA patients showed a significantly decreased number of febrile episodes and modification of their characteristics (mean duration of fever episodes, p<0.05; number of febrile episodes per year p<0.005). CONCLUSIONS: Deficient and insufficient vitamin D serum levels were found in most children with PFAPA syndrome, and hypovitaminosis D might be a significant risk factor for PFAPA flares. However, vitamin D supplementation seems to significantly reduce the typical PFAPA episodes and their duration, supporting the role of vitamin D as an immune-regulatory factor in this syndrome.