Alopecia areata is a/ an -
Autoimmune disorder
Allergic disorder
Anaphylactic disorder
Bacterial infection
Ans. is 'a' i.e., Autoimmune disorder Pathogenesis of alopecia areata1. Autoimmunityo Current evidence suggests that alopecia areata is caused by an abnormality in the immune system. This particular abnormality leads autoimmunity. As a result, body's own immune system attacks the hair follicles and disrupts normal hair formations. Autoimmune pathogenesis is supported by -The germinative zones of hair follicles are surrounded by T-lvmphocytes, where they are not normally present.Sometimes alopecia areata is associated with other autoimmune disorders, e.g. vitiligo, IL4, ulcerative colitis, hypothyroidism.# Frequency of type 1 DM is increased in relative of patients with alopecia areata but not in patient themselves --> alopecia areata may be protective against type 1 DM.2. Genetic factorso Besides autoimmunity genetic factors also have pathogenic role10-20% Patients give family historyfThere is polygenic inheritenceStrong association between alopecia areata and MHC class II, i.e. HLA-DR4, HLA DR-5, HLA DQ-3Genetic disorders like autoimmune polyglandular syndrome type I and Down s syndrome have high incidence of alopecia areata.
Alopecia