Everybody reacts differently, with most people requiring UV treatment two to three times per week.

Phototherapy

Ultraviolet (UV) therapy, often referred to as phototherapy or light treatment, is a psoriasis treatment that involves exposing the skin to a carefully measured dose of artificial ultraviolet (UV) light. Two types of UV light are typically used: ultraviolet A (UVA) and ultraviolet B (UVB). These procedures are usually done in a dermatologist's office.

Light therapy affects skin cell growth and the immune cells involved in psoriasis. Treatment involves entering a special light box and exposing all affected areas to UV rays for a specific period of time.

There are currently two types of UV treatment that are commonly used.

UVB treatment

Ultraviolet B (UVB) therapy is generally recommended for people with psoriasis who have lesions that cover significant areas of their body, making topical treatment difficult. Most people will receive two to three treatments per week. Dosages are determined by the dermatologist and tailored to the individual. Your dermatologist may recommend combining UVB treatments with topical or systemic treatments to improve its effectiveness, speed up results, and/or limit side effects by decreasing the number of treatments and the dosages of the medications.

Narrowband UVB

A form of UVB therapy, narrowband phototherapy utilizes a narrower spectrum of light than broadband UVB.

PUVA treatment (pronounced "poova")

PUVA (psoralen Ultraviolet A) combines UVA exposure with a photosensitizing agent that is taken internally in pill form, or topically in a bath solution.

UVA treatment is usually administered when psoralen levels in the skin are high. Depending on the type of oral PUVA, patients are instructed to take the psoralen pills between 1 to 3 hours before going inside the UVA light box. The amount of time spent under the lights depends on skin type (the darker or more tan you are, the more time it will take). Approximately 20 treatments are needed to see clearing.

Other important information you should know

All medicines have potential side effects and should be used cautiously and under the supervision of a healthcare professional. Some common adverse events associated with phototherapy include skin irritation, light sensitivity, and burning.