Psoralen plus UVA (PUVA) Therapy is a treatment method that combines a photosensitizing drug, psoralen, with exposure to ultraviolet A (UVA) light to manage skin conditions like psoriasis, eczema, and vitiligo. This therapy works by slowing down excessive skin cell growth and modulating the immune response, but it requires careful administration to minimize potential side effects such as skin aging and increased cancer risk.