Affecting over 5 million Americans, Psoriasis - an inherited skin disorder - grows with an estimated 200,000 new cases diagnosed each year. Psoriasis is characterized by inflammation, itching, thickening and scaling of skin. The thickened skin and scaly appearance can appear anywhere on the body, including the nails and scalp. Treatment is approached in three phases. It is important to note that the treatments will often alleviate symptoms, but there is currently not cure. First, topical creams or ointments are tried. The next phase is phototherapy, and lastly there are systemic treatments (oral medications).

Because topical treatments tend to need reapplication very often and systemic treatments can have a number of serious side effects, including death on rare occasions, Phototherapy tends to be the most preferred treatment, despite its time consumption and increased risk of photoaging (wrinkles and discoloration due to Ultraviolet light exposure) and future skin cancer development.

Photochemical interactions are the main interactions in the phototherapy of psoriasis. Ultraviolet (UV) light induces biologic reactions in skin cells that can result in clearing of psoriatic lesions. Rather than sunlight's full range of UV rays, psoriasis laser treatments utilize UV wavelengths from 300 to 313 nanometers.

PUVA, an acronym for Psoralen + UVA treatment for Eczema and Psoriasis, is a form of phototherapy utilizing UVA rays. In this treatment Psoralen (photosensitizing agent found in plants) is applied or taken orally to sensitize the skin, then the skin is exposed to laser produced UVA rays. Many times, nausea is experienced with ingested psoralens, making topical application a preferred choice for some psoriasis patients.

The psoralens allow a relatively lower dose of UVA to be used. When they are combined with exposure to laser emitted UVA, they are highly effective at clearing psoriasis. Like UVB light treatments, the reason remains unclear, though investigators speculate there may be similar effects on cell turnover and the skin's immune response.

Lasers clear psoriatic lesions by selectively destroying the blood vessels responsible for skin inflammation from the inside out, without damaging the surrounding skin. In general, two to six treatment sessions are performed at intervals of two to four weeks. Bruising and occasional crusting develops over the treated lesions, lasting approximately one week. Approximately 90% of people who try laser treatments report excellent results and about 40% were clear within two to five sessions.

Complete remissions have lasted as long as 48 months. By using lasers for phototherapy psoriasis treatment significantly reduces the amount of time that treatments take. It is entirely possible for psoriasis patients to have treatments during their lunch hour, not having to make scheduling allowances for their skin disorder.