The Wood’s lamp test is a diagnostic procedure used in dermatology to examine the skin for bacterial or fungal infections, pigment disorders, and other irregularities. It uses ultraviolet (UV) light, typically around 365 nanometers, to illuminate the skin in a dark room. Certain substances and organisms fluoresce (glow) under this light, helping doctors identify conditions such as vitiligo, tinea infections, or erythrasma. For example, fungal infections may show a green or yellow glow, while vitiligo appears bright white. The Wood’s lamp test is quick, painless, and noninvasive, making it a valuable tool for skin evaluation and diagnosis.