Is there an association of ABO blood groups and Rhesus factor with alopecia areata?

We conclude that there was no association between ABO blood group and AA, but the observed distribution of Rhesus blood group differed slightly but significantly from that of the healthy population. The result of the study shows a small but statistically significant difference in the Rh blood group between patients with AA and the healthy population blood groups. This result is important because it suggests that genetic factors may influence the development of AA. The role of blood groups in the development of AA remains to be determined. We believe that the studies which will be carried out in other centers with wider series will be more valuable to support this hypothesis.