Topical treatments (treatments that are applied to the skin's surface) are usually the first line of defense against psoriasis, but if the psoriasis is extensive or disabling, ultraviolet light treatment (phototherapy) can be used.
Phototherapy involves exposing the skin to wavelengths of ultraviolet light under medical supervision. Treatments usually take place in a doctor's office or psoriasis clinic. This webpage covers the different types of phototherapy available and how they are used to help you understand this treatment and decide, with the help of your doctor, if it is right for you.
UVB PHOTOTHERAPY
What is UVB and how does it work?
Present in natural sunlight, ultraviolet light B (UVB) is an effective form of ultraviolet radiation for treating psoriasis, eczema, and all other skin diseases. UVB radiation penetrates the skin and slows the abnormally rapid growth of skin cells. UVB treatment involves exposing the skin to an artificial UVB light source for a set length of time on a regular schedule under a physician's direction in a medical setting. Usually, Dr. Ethan Nguyen will require a patient to receive UVB treatment in the office or clinic for several weeks or until his or her skin condition is stable, and it is clear that the person responds to UVB. At that point Dr. Ethan Nguyen may then prescribe maintenance treatments.
There are two types of UVB treatment, broad band and narrow band. The major difference between broad-band and narrow-band UVB is that narrow-band UVB units emit a more specific range of UV wavelengths.
Several studies indicate that narrow-band UVB clears psoriasis and eczema faster and produces longer remissions than broad-band UVB. It is effective with two or three treatments per week, while in some cases, broad-band must be administered more frequently to be effective.
LASERS Targeted UVB therapy
The UVB laser, which is approved by the u.s. Food and Drug Administration (FDA) for psoriasis and vitiligo, emits a high-intensity beam of UV light that is very similar to the light delivered by narrow-band UVB units.
The laser beam is small(less than one inch in diameter)and can be targeted at selected areas of the affected skin.
How well an individual will respond to the treatment varies. It takes an average of 4 to 10 sessions to see results, depending on the severity of skin diseases. It is recommended that patients are treated twice per week, with a minimum of 48 hours between treatments.
Pulsed dye lasers
Like the UVB laser, pulsed dye lasers are approved for and are being used to treat chronic localized plaque lesions. Pulsed dye lasers emit a different form of light than UVB units and the UVB laser. These lasers emit pulses of high-intensity yellow light from the visual spectrum.
Pulsed dye lasers destroy the tiny blood vessels that contribute to and support the formation of psoriasis and other skin lesions. They have been in use for approximately 15 years for removing unwanted blood vessels and birthmarks, such as port wine stains. Investigators first reported that psoriasis could be cleared with pulsed dye lasers in 1990. In small studies in 1992 and 1995, improvements were seen in 5 of 8 patients and 6 of 10 patients, respectively. A larger study in 1996 reported significantly that remissions lasted in some patients up to 13 months. In a study published in July 2001, researchers reported significant clinical improvement in psoriasis lesions in eight patients after treatment, but complete clearance of lesions was not achieved.
PUVA
What is PUVA?
PUVA is an acronym for psoralen (a light-sensitizing medication) combined with exposure to ultraviolet light A (UVA). UVA, like UVB, is found in sunlight. By itself, however, UVA is not normally used to clear psoriasis. It is relatively ineffective unless used with a light-sensitizing medication such as psoralen (request the Psoriasis Foundation booklet for more about the beneficial effect of sunlight on psoriasis).
How does it work?
PUVA works to slow down the excessive cell reproduction of psoriasis and other skin diseases and can clear the symptoms for varying periods of time. Like UVB, it is used to treat moderate to severe psoriasis. It is also used to treat severe, disabling psoriasis that cannot be controlled by systemic drugs.
SUMMARY
Treatment with ultraviolet light is very effective for psoriasis, eczema and many other skin disorders, especially when topical treatments cannot be used. The key to success with phototherapy is consistency. It is also important that the potential risks be understood by patients. Long-term use can lead to skin damage, such as freckling and aging, or even rarely skin cancer. Side effects can be minimized, however, by carefully following safety precautions.