[Ultraviolet A-I phototherapy for skin diseases]

Favourable effects of sunlight on various skin diseases include inhibition of rapid proliferation of cells (psoriasis), modulation of cells in an inflammatory infiltrate (atopic eczema) and stimulation of proteolytic enzymes (scleroderma). The ultraviolet (UV) fraction of the solar spectrum is the most biologically active because it is almost completely absorbed by the skin. UVB and the combination of psoralens with UVA (PUVA) have become important therapeutic modalities, especially for psoriasis and eczema. Lamps producing long wave UV radiation are available: UVA-I light. Owing to its longer wavelength it penetrates more deeply into the skin and gives less risk of development of skin cancer than other forms of UV radiation. Good results are reported of application of UVA-I in patients suffering from atopic dermatitis, scleroderma, urticaria pigmentosa, and systemic lupus erythematosus.