Menu Healthy Lifestyle Diseases & Conditions First Aid Symptoms Tests & Procedures Videos Definitions FAQs Alopecia areataUpdated: 2020-05-22OverviewAlopecia areata is a type of patchy hair loss that occurs suddenly and usually starts with 1 or more circular bald patches that may overlap. It occurs when the immune system attacks hair follicles, and may be brought on by severe stress.TreatmentsTreatment may address any underlying conditions and includes topical scalp medications. © 1998-2022 Mayo Foundation for Medical Education and Research(MFMER). All rights reserved. Terms of Use