Natural sunlight is composed of both ultraviolet A (UVA) and ultraviolet B (UVB) light. UVA light penetrates the skin more deeply than UVB light. However, UVA light is not effective for treating psoriasis unless combined with Psoralen, a medication that increases sensitivity to light. Together, the treatment is called Psoralen + UVA (PUVA). PUVA treatment is also referred to as photo-chemotherapy.
What does it involve?
PUVA treatment is believed to work by penetrating the skin and slowing down the growth of skin cells. PUVA treatment works best when UVA light is delivered consistently to all affected areas.
You will receive PUVA therapy at a clinic two or three times a week. You will take Psoralen approximately one hour before receiving UVA treatments. Psoralen may be taken either orally as a gelatin capsule or topically by immersion in a bath filled with diluted medication. Taking Psoralen capsules with food may help prevent nausea. The amount of exposure time required for UVA treatments is shorter for those with paler skin and longer for those with darker skin.
Most people see improvement after approximately 15 PUVA treatments.
Most physicians agree that tanning beds do not provide safe or effective therapy for psoriasis.
PUVA treatments can improve the appearance and symptoms of psoriasis.
In a 2006 study, 93 people with plaque psoriasis were given either narrow-band UVB or PUVA treatments. The results showed that 84 percent of those who received PUVA achieved clearance from psoriasis, compared with 65 percent of those who received narrow-band UVB. In addition, those who received PUVA achieved clearance after fewer treatments than those who received UVB and maintained remission for longer.
PUVA treatment may not be effective for treating your psoriasis.
You must visit the clinic regularly on an ongoing basis for PUVA treatments.
Psoralen may cause nausea.
With any phototherapy, your psoriasis may worsen at first before it begins healing. Redness and itching are common side effects of phototherapy.
PUVA treatment is not appropriate for pregnant or breastfeeding women or anyone (male or female) who is trying or planning to conceive a child.
Exposure to ultraviolet light, including during PUVA treatments, can cause premature aging and sunburn and increase your risk of developing skin cancer.
Some psoriasis medications such as Elidel and Protopic can increase your risk for sunburn during phototherapy.
If you are receiving light therapy, you should limit your exposure to sunlight.