Practical pearls in phototherapy

The following tips are suggested for phototherapy: (i) calibrate the unit with a radiometer every 2-4 weeks; (ii) change all bulbs at the same time every 8-10 months for regularly used machines or when the UV meter shows that the power has reached 3 or 4 mW/cm²; (iii) avoid phototherapy sessions on consecutive days to prevent burn on burn; (iv) in the event of a burn, reduce the last PUVA or UVB dose by 50%, reinitiating when erythema has fully disappeared, which might take two days to two weeks; (v) nausea from oral psoralens can be avoided by taking it with a fixed amount of milk or food, taking an antiemetic with this meal prior to dosing, taking five ginger tablets 15 minutes before dosing, or dividing the dosage; (vi) to achieve 0.03% concentration of 8-methoxypsoralen for hand and foot soak PUVA, dissolve a 10-mg tablet or 1.0 cc of Oxsoralen^® solution 1% in 3 l of water; and (vii) to achieve 0.000075% concentration of 8-methoxypsoralen for full-body soak PUVA, dissolve 60 mg 8-methoxypsoralen in 80 l of water (i.e. a bath tub).