Background Alopecia areata is considered to be an autoimmune disease characterized by T‐cell response and production of cytokines around the anagen stage. Aim of the study The aim of this study was to assess T cells in blood using immune biomarkers (CD3, CD4, and CD8) in patients with AA and AU compared with healthy individuals. Materials and methods This study was carried out at private clinic and in the Department of Dermatology in Al Karama Teaching Hospital. The study groups included 58 patients from different geographic areas in Iraq, with ages ranging from 5 to 48 years from the end of August 2019 to the January 2020; AA patient group included 19, AU patient group included, 11 and control group included 30 with no scalp or body lesions in their disease history. All patients were clinically diagnosed to detect clinical types of disease in the scalp, in the body, and any hair‐bearing area. Venous blood samples were collected from all participants where CD3 T cell, CD4 T cell, and CD8 T cell in whole blood were estimated by flow cytometry technique. Results The present study has found the males are more susceptible to infection than the females in both types of disease. There was no significant difference (p > 0.05) detected for immune biomarkers (CD3, CD4, and CD8) in blood between patient groups in comparison with healthy individuals, but there was a significant decrease (p ≤ 0.05) in immune biomarkers (CD8, CD3) according to stress status in AU and in CD8 T cell between patient groups. CD4/CD8 ratio increased in alopecia patients. Conclusion In current study, There was no significant difference detected for biomarkers (CD3, CD4, and CD8) in blood between patient groups and healthy control, but significantly decrease in CD8 T cell and CD3T cell according to stress in AU, and in CD8T cell between patient groups according to stress This research may have proven one of the theories. Study of CD markers receptors and B cell receptors these will help for future studies.