Introduction Alopecia areata (AA) is a relatively common reversible patchy hair loss of the scalp. It is usually manifested as patchy areas of complete hair loss on the scalp and sometimes with or without other body parts that can progress to complete loss of all body hair. This disorder affects all age groups, with a higher incidence in children and adolescents. AA is an autoimmune disorder characterized by hair cycle dysfunction with peribulbar and perifollicular mononuclear cell infiltrates. Aim To estimate interleukin-17A (IL-17A) serum level in patients with AA as well as study its relationship with the age of the patients, severity, and recurrence of disease. Patients and method s The study was carried out in Outpatient Clinic of Dermatology, Venerology, and AndrologyDepartment,ZagazigUniversityHospitals,on45patientswithAAofboth sexes.Resultswerecomparedwith45healthyparticipantswithmatchedage(5–50 years). Results The present study included two groups: patient group included 45 patients diagnosed clinically with AA and control group included 45 age-matched and sex-matched healthy individuals. Conclusion The significantly higher levels of serum IL-17A in patients with AA suggest a possible role of IL-17A as a proinflammatory cytokine in the pathogenesis of AA and that IL-17A l