Dr. Prystowsky uses phototherapy to treat psoriasis, vitiligo, polymorphous light eruption (sun allergy), cutaneous T cell lymphomas (CTCL), pityriasis rosea, and other disorders. Phototherapy exposes the affected skin to ultraviolet light that slows the growth of new skin cells in psoriasis, enhances repigmentation in vitiligo, and reduces inflammation in eczema. In the case of sun allergy, it causes tolerance to develop. And in CTCL, the light eliminates the lymphoma cancerous cells from the skin. This may be done using UVA or UVB light, depending on each individual case.

Phototherapy is usually administered two to three times a week for an indefinite period to maintain control of the skin disorder. Results may be visible within two weeks and usually continue to improve as treatment continues. Many patients see effective relief from this FDA approved treatment.