<prompt> PUVA treatment is not used in:MelasmaVitiligoPsoriasisCutaneous T cell lymphoma  <response>: Ans: A Melasma Ref: Rooks Dermatology, 8th edExplanation:PUVA TherapyPsoralens UV-A radiationThree Psoralens are used clinically8 methoxypsoralen 8 MOP5 methoxypsoralen 5 MOPTriniethyl psoralen TMPThey are active only when combined w ith UVA radiation.It interferes with DNA synthesis and blocks epidermal cell proliferation.Also has immunomodulatory and immunosuppressive effects.Induced epidermal thickening and melanogenesis.DosageOral 8-MOP given in a dose of 0.6 -0.8 mgkg weightday.Two hours later, patient is exposed to UV-A radiation at a dose of 1 Joulesquare cmUV-A dose gradually increased depending on skin type and onset of erythemaTherapy given 2 -3 times per weekNumber of exposures required for control: 15 - 25IndicationsPsoriasisVitiligoPhotodermatosesCutaneous T-eell lymphomaSide effectsNausea and VomitingCutaneous:Acute sunburnIrreversible pigmentationPUVA LentigenesActinic keratosesPremature aging of skinOcular - Cataract Prevented by using sunglasses during treatmentCarcinogenesis 