Practice when minimal phototoxic and minimal erythema doses are not determinable

摘要

We have come across individual cases of inappropriate management of patients in whom no minimal photo-toxic dose (MPD) was detectable on readings prior to starting psoralen and ultraviolet A (PUVA) photoche-motherapy. In particular, a patient attending one of our Tayside phototherapy centers had no detectable phototoxic response on MPD readings. In spite of this, she went on to have over 20 treatments starting at a dose based on the highest test dose (to which there had been no response) without improvement of her psoriasis. It was only following review at that stage that her MPD testing was repeated after administering a higher psoralen dose and her psoriasis subsequently responded to PUVA rapidly.