PUVA is a photochemotherapy method applied by orally taking a medication called psoralen, followed by exposure to ultraviolet A (UVA) light. Psoralen acts by sensitizing the skin to sunlight and modulating the function of the immune system. Currently, PUVA is widely used in the treatment of various dermatological conditions, primarily including psoriasis, vitiligo, atopic eczema, severe lichen planus, alopecia universalis, chronic pruritus, parapsoriasis, and mycosis fungoides (a type of skin cancer).