Title : Simultaneous Alopecia Areata in Identical Twins: A Rare Presentation from Saudi Arabia
Abstract:
Background: Alopecia areata (AA) is a chronic, relapsing autoimmune disorder targeting the hair follicle. Its clinical spectrum ranges from patchy alopecia to total hair loss (alopecia totalis or universalis), with variable progression and recurrence. While a genetic predisposition is well-established, reports of monozygotic twins experiencing simultaneous AA onset are exceedingly rare.
Case presentation: We report the unique case of 6-year-old identical twin girls who presented with patchy hair loss of one month’s duration, discovered simultaneously by their mother. The lesions appeared two weeks apart, both localized as a single, non-inflammatory, asymptomatic circular bald patch on the vertex. Dermoscopic examination revealed hallmark features including yellow dots, black dots, broken hairs, tapering hairs, and short vellus hairs. No nail involvement, systemic symptoms, or other dermatological issues were present. Both twins had no prior history of scalp disorders, infections, or trauma. Topical clobetasol propionate once daily at night was initiated and led to satisfactory improvement in both patients.
Conclusion: The identical distribution and similar timing of presentation suggest a strong genetic influence, possibly accompanied by shared environmental triggers. To date, only a few cases have described such simultaneous onset in identical twins, making this case among the rarest presentations of AA. Our findings emphasize the importance of considering genetic and epigenetic factors in AA pathogenesis and highlight the value of early diagnosis and targeted management in pediatric patients. Further studies on identical twins could yield valuable insights into the interplay between heredity and environmental triggers in autoimmune hair disorders.
