Ultraviolet (UV) A-1 phototherapy is now available for a variety of skin diseases. Increasingly since 1995, there have been investigations of the efficacy of UVA-1 (340-400 nm) therapy for sclerotic skin diseases. Most studies undertaken treated patients who had localized scleroderma, but UVA-1 phototherapy is currently also used for other sclerotic skin conditions.

We sought to assess the efficacy, biological effects, and side effects of UVA-1 in a variety of sclerotic skin diseases (localized scleroderma, eosinophilic fasciitis, chronic graft-versus-host disease, lichen sclerosus et atrophicus, scleredema adultorum, necrobiosis lipoidica, POEMS disease, pansclerotic porphyria cutanea tarda, and drug-induced scleroderma-like disorders).

The authors searched for publications dated between January 1996 and November 2007 in the computerized bibliographic database, PubMed. PubMed was searched using medical subject heading terms and open searches to retrieve the latest reports.

The evidence based on research concerning the effect of full-spectrum UVA (320-400 nm) and UVA-1 on these skin diseases is still growing, and appears promising. Up until now, good results are shown for all different doses (low, medium, and high) UVA-1 and UVA. There are insufficient data regarding use of high-dose UVA-1 and there are no comparative studies to make a clear assessment regarding the superiority of low-, medium-, or high-dose UVA-1 therapy. Although UVA-1 has various effects on, for instance, fibroblasts and inflammatory cells, the precise mode of action remains obscure. The main short-term side effects of UVA-1 therapy are erythema, pruritus, xerosis cutis, tanning, and recrudescence of herpes simplex infection. More studies are warranted to investigate the potential long-term risk of photoaging and skin cancer. Currently, UVA-1 is considered to be less carcinogenic than psoralen plus UVA (PUVA).

Because of the limited availability of randomized controlled trials and large cohort studies, it is difficult to draw firm conclusions on the long-term efficacy, optimum dose, and best treatment regimens for UVA-1 when administered to patients with sclerosing skin disorders.

Full-spectrum UVA and UVA-1 phototherapy seem effective in the treatment of sclerotic skin diseases based on data retrieved from the literature. UVA-1 treatment can shorten the active period of localized scleroderma and pseudoscleroderma and prevent further disease progression, including contractures. Further investigations will be needed to determine any additional biological effects of UVA-1. Although long-term side effects are not yet known, UVA-1 might develop into a promising beneficial and well-tolerated treatment in the therapeutic armamentarium for sclerotic skin diseases. Long-term studies in large groups of patients are clearly needed.