Narrowband UVB is the most common form of phototherapy used to treat skin diseases. “Narrowband” refers to a specific wavelength of ultraviolet (UV) radiation, 311 to 312 nm. UVB phototherapy was formerly provided as a broadband source (290 to 320 nm).
The narrowband range of UV radiation has proved to be the most beneficial component of natural sunlight for psoriasis. Narrowband UVB may also be used in the treatment of many other skin conditions including atopic eczema, vitiligo, pruritus, lichen planus, polymorphous light eruption, early cutaneous T-cell lymphoma and dermographism.