Evolution of targeted phototherapy for psoriasis

Psoriasis is a major inflammatory disorder in the dermatological field. Phototherapy is effective and safe for psoriasis vulgaris. Narrow-band ultraviolet (UV) B and psoralen plus UVA are known to be the common modality as conventional non-targeted phototherapy. Non-targeted phototherapy making unnecessary irradiation to the unaffected skin may cause long-term adverse effects of UV. Targeted phototherapies with advantages, for example, higher dosages for lesional skin, a rapid clearing and longer remission rates, have been developed. Targeted phototherapies are preferably used for childhood, palmoplantar psoriasis, scalp and nail psoriasis as well as refractory lesions remained after whole-body UV therapy. Light sources of targeted phototherapy include broad-band UVB, narrow-band UVB, 308-nm excimer laser and light, 307-nm excimer light and 312-nm flat-type fluorescent lamp. This comprehensive review focuses recent evolution of target phototherapy for the treatment of psosriasis.