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
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
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:
Children under age 12, because the UV light
therapy may cause cataracts.
People who have diseases that make
their skin more sensitive to sunlight (such as
Fertile men and women who do not
use birth control. There is a small risk of birth defects.
women, because of possible effects on a
How Well It Works
Many studies have shown that PUVA is effective in treating
When PUVA is used to treat psoriasis, short-term side effects
Skin redness, headache, nausea, and
The spread of psoriasis to skin that
was not affected before (Koebner's response).
Nausea from the
The most significant potential long-term effect of PUVA treatment
is an increased risk of some types of cancer.
PUVA treatments with cyclosporine have shown a significant
increase in the risk of
squamous cell cancer.2 A serious form of skin cancer, melanoma, has also been
The male genitals are highly susceptible to the
cancer-causing effects of both PUVA. Female genitals do not seem to be
Other long-term side effects when using PUVA to treat psoriasis
Premature skin damage associated with sun
Discolored spots on the skin.
the scaly layer of skin caused by exposure to sunlight (actinic
Cataracts. Cataracts may be avoided by
wearing goggles during UVA treatments and sunglasses that block UV light when
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.
How this information was developed to help you make better health decisions.