Most scholars believe that it is a tissue-specific T-cell-mediated autoimmune disease that is associated with an imbalance in the ratio of CD4 T-lymphocytes to CD8 T-lymphocytes around the hair follicle. Psychological factors, malnutrition, and local microcirculatory disorders also play an important role in its development. In most cases, hair loss can recover on its own. Severe cases require pharmacological treatment. Commonly used methods can be topical or local injection of corticosteroids, topical minoxidil solution, etc. to promote hair growth. However, there are some patients who are exceptionally stubborn and resistant to multiple treatments. In recent years, scientists have found that a new treatment method, 308 nm excimer laser, has shown better efficacy for refractory baldness that has not been treated with common methods. The mechanism of action may be that the 308 nm excimer laser induces apoptosis of T-lymphocytes, inhibits cytokine production and antigen presentation by Langerhans cells, and reduces the effect of immune factors on hair destruction.