SEASONAL-VARIATION IN THE ONSET OF WEGENERS GRANULOMATOSIS, POLYARTERITIS-NODOSA AND GIANT-CELL ARTERITIS

Objective. The hypothesis of a seasonal pattern in the onset of sympto ms for some vasculitides has been raised in previous small studies. Me thods. Using the data collected by the American College of Rheumatolog y (ACR) Subcommittee on Classification of Vasculitis, we specifically tested for a higher proportion of onset of symptoms in winter, lower i n summer, and intermediate for the other seasons for polyarteritis nod osa (PAN) and Wegener's granulomatosis. We also tested for a higher pr oportion of onset of symptoms in the spring-summer months for giant ce ll arteritis (GCA). Results and Conclusions. The results of our study support the hypothesis of a seasonal trend for the onset of symptoms o f Wegener's granulomatosis (p = 0.04) as described previously. No seas onal pattern was found for the other vasculitides studied (PAN and GCA ).