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Updated: Sep 28, 2026

Minimal Erythema Dose (MED) Testing
Published on: May 28, 2013
Vitamin D and psoralen plus UVA radiation
1Department of Medicine, University of Barcelona, Spain.
Abstract:
Psoralen plus UVA (PUVA) light is a very effective and widely used monotherapy for psoriasis. However, it is associated with cumulative long-term risks, including premature cutaneous aging and skin cancers. Several studies have shown that the addition of calcipotriene ointment to PUVA radiation has a UVA-sparing effect, clearing psoriatic lesions sooner with lower cumulative doses of UVA radiation compared with doses of PUVA radiation alone. A recently completed multicenter study in Spain demonstrated that the use of calcipotriene cream plus PUVA radiation was also safe and effective for the treatment of plaque psoriasis, achieving results that were similar to those obtained with calcipotriene ointment plus PUVA radiation. Because creams are cosmetically more acceptable and less likely to stain, patients may prefer calcipotriene cream formulations. When used in conjunction with PUVA radiation, calcipotriene should be applied after the UVA radiation treatment because standard doses of UVA radiation have been shown to inactivate calcipotriene.
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