PUVA - Phototherapy

PUVA is a form of phototherapy for the treatment of psoriasis that combines a psoralen medication with ultraviolet A light. (UVA rays). "Psoralen” + “UVA” = PUVA.

PUVA is a well-established and effective psoriasis treatment. It slows down the excessive skin cell growth and, after several sessions, can provide prolonged clearance of psoriasis lesions.

Multiple treatments are required for optimal results.  When used appropriately, PUVA clears psoriasis in nearly 85% of cases and results in long remission times. Maintenance treatments may be recommended 1-2 times per month to remain clear.

PUVA is especially useful for people with moderate to severe plaque psoriasis, guttate psoriasis, and psoriasis of the palms and soles of the feet. Erythrodermic psoriasis also responds to PUVA, but not as well as these other forms.

PUVA may be used in combination with other psoriasis treatments. Rotating treatments may recommended to reduce the total exposure to UVA rays and reduce the chances of developing long-term side effects. PUVA may be used for 12 to 24 months and then replaced with Soriatane®, cyclosporine, or biologics.


Psoralen sensitizes the skin to light. It is applied to the surface of the skin or taken by mouth before being exposed to UVA light. The UVA light is ineffective without the initial use of psoralen.

For optimal results, the exposure to UVA rays must occur when the psoralen levels in the skin are highest. If psoralen is taken orally, this is usually 1-2 hours after ingestion. If the psoralen is applied to the skin (“paint”, or “soak”), the UVA exposure should occur within 15 minutes.

Your doctor may recommend the use of topical or oral psoralen depending on several factors. Topical PUVA is often suggested for people with resistant patches of psoriasis because it provides a higher concentration of psoralen on the lesion. And some people cannot tolerate the nausea and itching associated with oral psoralen. However, topical PUVA increases the risk of the skin being burned during treatment. And since it is more labor intensive, topical psoralen may not be appropriate for people with limited abilities.

UVA Light

The UVA is administered in a light unit lined with ultraviolet lamps. Most UVA units are big enough to allow standing within the box so that the most of the body is exposed to UVA rays. A large light unit may be called a “light box”. Smaller UVA units are available for treating specific regions of the body, such as the hands and feet.

For people just starting PUVA therapy, the prescribed exposure to UVA rays is very short, and may vary from 30 seconds to several minutes. The exposure time is gradually increased to 20 minutes or longer.

Because oral psoralen can sensitize the eyes, as well as the skin, UVA-blocking goggles must be worn during treatment.

Risks of PUVA

People undergoing PUVA therapy should avoid the sun as much as possible because psoralen makes the skin susceptible to sunburn and other damaging effects of sunlight.

In addition, UVA-blocking glasses must be worn during daylight hours for 24 hours after PUVA therapy. These special sunglasses must be worn indoors and in the car because UVA rays can penetrate glass. (Although many sunglasses state that they provide UV protection, most do NOT provide sufficient protection from UVA rays.)

PUVA poses several long-term risks, including premature aging skin, an increased chance of developing cataracts and skin cancer, particularly squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). Lifetime monitoring for skin cancer is recommended.

PUVA is not recommended for pregnant or nursing women, nor people with a history of skin cancer, liver disease, or medical conditions that require sun avoidance, such as lupus, porphyria, or skin cancer.

Although PUVA is not usually recommended for children, it may be used if necessary to avoid undesired side effects of systemic medications, such as cyclosporine or methotrexate.

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Last updated: 1/8/2019