Alopecia Areata and Season of Onset: A Retrospective Study of 492 Cases

January 2024 in “ Annals of Dermatology ”

Sang Hoon Lee, Seung‐Won Jung, Won‐Soo Lee

alopecia areata SALT50 immune privilege collapse vitamin D deficiency

TLDR Winter-onset alopecia areata patients are more likely to regrow hair within a year compared to spring-onset patients.

This retrospective study of 492 alopecia areata (AA) cases examined the impact of the season of onset on disease severity and prognosis. While no significant differences were found in initial severity and clinical progress based on the season, winter-onset AA patients were more likely to achieve significant hair regrowth (SALT50) within 1 year compared to spring-onset patients. The study suggests that winter's low temperature, humidity, and potential vitamin D deficiency may influence AA's pathogenesis and prognosis, though seasonal factors do not significantly affect the primary role of immune privilege collapse in AA. The study calls for further research on AA's long-term prognosis and notes limitations like recall bias and the inability to measure vitamin D levels.