Phototherapy involves the use of ultraviolet light to treat the skin. Ultraviolet light is the same rays that are in sunlight. Patients with more extensive skin involvement are often prescribed phototherapy when topical treatments prove impractical or ineffective. There are different types of phototherapy based on the different wavelengths of ultraviolet light used during treatment. These include ultraviolet B (UVB- Broad or Narrow Band) or PUVA (Psoralen medication+UVA)
UVB phototherapy has been shown to be effective in cases in which the skin lesions are thin, without significant thickness. Treatments are typically conducted in a dermatology office with the use of a specially calibrated light box. Improvement in skin lesions is often not observed until the patient has received approximately 20-40 treatments. UVB phototherapy (Narrow or Broad Band) begins with small doses of light given 2-3 times per week with gradual increases in dose over time. Side effects of phototherapy include temporary redness or burning of the skin. Prolonged phototherapy administration can increase overall skin cancer risk.
PUVA phototherapy combines the use of the photosensitizing drug Psoralen (oxsoralen, methoxsalen, 8-MOP) with ultraviolet light of a specific wavelength (UVA). PUVA phototherapy is equally effective in early stage disease, but most effective for skin lesions that involve large surface area and demonstrate some degree of thickness. Similar to UVB phototherapy, 20-40 treatments delivered 2-3 times per week are usually needed to produce clearing. Patients take Psoralen pills 1.5 to 2 hours prior to being treated with UVA light. Patients are required to wear UV-protective eye shields for 24 hours after each treatment in order to protect the retina from photosensitive reactions. Some patients develop stomach upset when they take the oral Psoralen. Long-term complications of PUVA phototherapy include the development of skin cancers. PUVA phototherapy is often combined with other forms of systemic therapy.
Phototherapy for the Treatment of CTCL/MF. Holly A. Kerr, M.D., Andrew P. Kontos, M.D., and Henry W. Lim, M.D.