Phototherapy is the use of non-ionizing electromagnetic energy, typically ultraviolet wavelengths, for therapeutic effect. Commonly used wavelengths are broad band UVB (BB-UVB), narrow band UVB (nbUVB) and UVA. nbUVB is considered the safest and most effective wavelength for treatment of psoriasis. UVA is used primarily for photochemotherapy (PUVA), while UVA1 may be useful for atopic dermatitis and scleroderma. Ultraviolet radiation causes biological effects when it is absorbed by various molecules in the skin. Importantly, UVR produces alterations in both local and systemic immune response.
The conditions most commonly treated with phototherapy are:
- psoriasis (most common);
- atopic dermatitis; and
- other dermatitis.
Other possible indications include:
- alopecia areata;
- pityriasis rosea;
- cutaneous T-cell lymphoma (CTCL);
- polymorphous light eruption and other photodermatoses;
- lichen planus;
- generalised pruritus; and
- pityriasis lichenoides
During the course of treatment, patients typically are seen 3x/week for therapy. Treatment may be either in a light box for widespread skin disease, or with a hand or foot unit for localized involvement. The Excimer laser can also be used for localized lesions.
Phototherapy is very effective in treating a variety of dermatoses, but a committed patient is required due to the frequency of required office visits. Home light-therapy units are available for use under physician supervision and will sometimes be reimbursed by insurance carriers.