Chapter 54 - Therapeutic Photomedicine

Abstract

Phototherapy is an effective, low-cost, and safe treatment for many common dermatologic conditions, including psoriasis and vitiligo, and rarer conditions like cutaneous T-cell lymphoma. Light-based therapies generally work by either locally destroying or suppressing T-cell-based immune responses or creating toxic products that destroy target cells. Narrow-band ultraviolet B (UVB) is the most widely used phototherapy, supplanting both oral psoralen + ultraviolet A (PUVA) and broad band UVB therapy in recent years due to its relative efficacy and long-term safety profile. New light-based technologies continue to be developed and can be increasingly targeted to specific body sites or conditions, such as the excimer laser and photodynamic therapy. UVA-1 therapy can target difficult sclerotic skin conditions like morphea or the skin symptoms of systemic sclerosis. Combining phototherapy with other systemic and topical medications has been common for years (such as oral retinoids with PUVA or the use of topical psoralens in PUVA [topical or bath PUVA] to reduce side effects). Newer agents are also being successfully combined with phototherapy, such as tofacitinib and UVB for vitiligo or biologic medications with UVB in psoriasis. Phototherapy can be used in clinical office or home settings, depending on the patient situation, with similar efficacy and cost.