When individuals fail to respond to topical corticosteroids, the physician may offer an alternative therapy. Psoralen is frequently combined with ultraviolet therapy in the treatment of Vitiligo.
The treatment is ore effective than topical steroids and also more predictable. The treatment is widely available in the USA. Like topical steroids, psoralen phototherapy also depigments the white spots. The treatment duration again is long and there is the potential of side effects. Unlike the steroids, these side effects of this therapy are much more severe
Psoralen is a chemical which has the ability to react with UV light. When this reaction occurs, darkening of the skin occurs. Psoralen can be administered by mouth or may be applied topically on the skin. Following this, UV light therapy is administered, the timing of the UV light is critical to success. When the psoralen is applied topically, the UV light is applied to the skin.
Psoralen phototherapy is best done in a physician's office to limit the side effects. After the therapy, it is mandatory that individuals avoid sunlight
Topical psoralen Photochemotherapy. There are many individuals ho has isolated small patches of Vitiligo. When the Vitiligo is limited and the individual is a child, topical psoralen phototherapy is the ideal method for treatment. All treatments are done in the physician's office.
Each treatment session is done under the supervision of a health care profession and administered twice a week. On the day of treatment, psoralen is liberally applied on the white skin patch for about 30 minutes. The UV light is then exposed to the skin patch. Initially the UV light exposure is only a few minutes and then the duration of exposure is increased progressively over the next few weeks. With time, the white skin is slowly replaced by pinkish discoloration and eventually normal skin is evident.
To prevent any side effects, after each treatment in the physician's office, the skin is thoroughly washed with water. Once the skin is dry a sunscreen is applied.
There are three major potential side effects of topical PUVA therapy include
- severe sunburn and blistering
- too much repigmentation or darkening (hyperpigmentation) of the treated patches
- increased risk of skin cancer
These side effects can be minimized by avoid sun after each treatment. The side effects do reverse with time but the sun burn can cause moderate pain and distress while it is present.
Psoralens can also make the eyes very sensitive to light and thus during the procedure, the eyes must be protected. In addition, after the procedure, one is highly encouraged to wear sun glasses to prevent eye damage which eventually results in the formation of cataracts
PUVA is not usually used in children under the age of 12, in pregnant or breast feeding women, or in individuals with certain medical conditions.
PUVA does not work in all individuals and the chance of success ranges anywhere from 50-60%. Vitiligo patches on the face, trunk, arms and legs respond best to this therapy. Hands and feet generally do not respond at all to this type of therapy.
The major set back of psoralen therapy is that it has to be done for at least 12 months to see some benefit.
In the last decade, there is some evidence that UV B light may be safer and just as effective as UV A light