Psoralen and UVA Light Therapy (PUVA) for Psoriasis
Psoralen medicines are available as pills, lotions, or bath salts. A psoralen medicine is taken 1½ to 2 hours before you are exposed to ultraviolet A (UVA) light (PUVA). This treatment is repeated 2 to 3 times a week. The dose of medicine is not increased, but the amount of light may be increased.
Goggles should be worn to protect eyes during UVA treatment. Special UVA-blocking glasses should be worn for 24 hours after PUVA therapy. Men should protect their genitals from UVA exposure during treatments.
Psoralens may also be used in a form that can be put into your bath water. This form causes greater sensitivity to UVA than the oral medicine, so lower doses of UVA can be used.
How It Works
Psoralens increase the skin's sensitivity to UV light, including sunlight. They are used to improve the effectiveness of UV light therapy for psoriasis.
It is thought that PUVA therapy reduces the excess growth of skin cells. It also weakens the immune system.
Why It Is Used
PUVA is used to treat moderate to severe psoriasis (covering more than 20% of the skin).
PUVA is used to treat psoriasis that has not responded to creams, ointments, or tar products used with UV exposure (phototherapy). It should be used in the lowest doses possible. Higher doses and more exposure increase the risk of skin cancer.
Psoralens should not be used by:
How Well It Works
Many studies have shown that PUVA is effective in treating psoriasis.1
When PUVA is used to treat psoriasis, short-term side effects include:
The most significant potential long-term effect of PUVA treatment is an increased risk of some types of cancer.
Other long-term side effects when using PUVA to treat psoriasis include:
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
Psoralens applied to the skin (topical) may help to avoid some side effects of oral medicines used for PUVA. They may be especially helpful when psoralens taken by mouth (oral) cause severe nausea. Topical psoralens may be used for psoriasis that affects only a small part of the skin.
Topical psoralens, such as those given in bath water, are as effective as oral psoralens. But if the light treatments are given in a doctor's office, a topical psoralen may be less convenient.
eMedicineHealth Medical Reference from Healthwise
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