UVA1 phototherapy is a specialized treatment that utilizes long-wave ultraviolet A (UVA) light to target specific skin conditions. Unlike UVB or UVC rays, UVA1 light has longer wavelengths (340-400 nm) that penetrate deeper into the skin without causing sunburn. This makes it effective for treating conditions that affect the deeper layers of the skin, such as scleroderma, atopic dermatitis, and localized scleroderma (morphea).