Abstract
BACKGROUND/PURPOSE: Alopecia areata (AA) is a non-scarring autoimmune hair loss disorder. Although phototherapy has been utilized to treat AA, its efficacy and mechanisms remain unclear. This study aimed to evaluate the effectiveness of phototherapy in AA and determine whether treatment outcomes vary depending on patient characteristics. METHODS: We retrospectively reviewed 49 patients with various types of AA who received at least 10 sessions of either local or whole-body phototherapy. The severity of hair loss was assessed using the Severity of Alopecia Tool (SALT) score. Patient demographics, disease type, clinical severity, and laboratory data were analyzed in relation to treatment outcomes. RESULTS: Of the 49 patients, 32 received local phototherapy and 17 received whole-body irradiation. There was no significant difference in the SALT improvement rate between local and whole-body irradiation. Significant factors contributing to treatment response included first-onset AA (p = 0.03), treatment initiation within 1 year of onset (p = 0.0069), and age over 40 (p = 0.0027). Patients with multiple or totalis types of AA demonstrated better responses compared to universalis or ophiasis. Hair regrowth was typically observed after 20-30 treatment sessions. CONCLUSION: Phototherapy is an effective treatment for certain subtypes of AA, especially when initiated early after disease onset. Local irradiation showed comparable effectiveness to whole-body irradiation. These findings support the early initiation of phototherapy as a therapeutic strategy for AA, particularly in older patients and those with limited disease duration.