2.  Is alopecia areata hereditary?
Yes, heredity plays a role. In one out of five persons with alopecia areata, someone else in the family also has it. Those who develop alopecia areata for the first time after the age of thirty years have less likelihood that another family member will have it. Those who develop their first patch of alopecia areata before the age of thirty have a higher possibility that other family members will also have it.

Alopecia areata often occurs in families whose members have had asthma, hay fever, atopic eczema, or other autoimmune diseases such as thyroid disease, early-onset diabetes, rheumatoid arthritis, lupus erythematosus, vitiligo, pernicious anemia, or Addison's disease.