Phototherapy lamps are highly effective at treating a variety of skin conditions, especially psoriasis,vitiligo, eczema, acne.  Ultraviolet B, UVB, is present in natural sunlight and when emitted at the proper wavelength will penetrate the skin to slow down the rapid growth of skin cells below the epidermal surface that cause Psoriasis.  

Broad band UVB lamps are commonly used to treat skin conditions, although it can be less effective in areas of skin folds. Narrow-band UVB lamps emit a narrower range of UVB wavelengths and can be effective in hard to reach areas including skin folds.  

UVA phototherapy lamps are also used in conjunction with UVB lamps and medication to treat certain medical conditions.  UVA, UVB and narrow-band UVB are all used to treat acne, eczema and Psoriasis, while vitiligo, a skin condition caused by a loss of melanin that leaves white blotches on the skin, is effectively treated primarily with narrow-band UVB phototherapy lamps.