The following information if from the National Institute of Health website1.
Light Therapy
Natural ultraviolet light from the sun and controlled delivery of artificial ultraviolet light are used in treating psoriasis. It is important that light therapy be administered by a
doctor, since spending time in the sun or a tanning bed can cause skin damage and
increase the risk of skin cancer.
Sunlight. Much of sunlight is composed of bands of different wavelengths of
ultraviolet (UV) light. When absorbed into the skin, UV light suppresses the
process leading to disease, causing activated T cells in the skin to die. This
process reduces inflammation and slows the turnover of skin cells that causes
scaling. Daily, short, nonburning exposure to sunlight clears or improves
psoriasis in many people. Therefore, exposing affected skin to sunlight is one
initial treatment for the disease.
Ultraviolet B (UVB) phototherapy. UVB is light with a short wavelength that is
absorbed in the skin's epidermis. An artificial source can be used to treat mild
and moderate psoriasis. Some physicians will start treating patients with UVB
instead of topical agents. A UVB phototherapy, called broadband UVB, can be
used for a few small lesions, to treat widespread psoriasis, or for lesions that
resist topical treatment. This type of phototherapy is normally given in a doctor's
office by using a light panel or light box. Some patients use UVB light boxes at
home under a doctor's guidance.
A newer type of UVB, called narrowband UVB, emits the part of the ultraviolet
light spectrum band that is most helpful for psoriasis. Narrowband UVB
treatment is superior to broadband, but it is less effective than PUVA treatment
(see next paragraph). It is gaining in popularity because it does help and is more
convenient than PUVA. At first, patients may require several treatments of
narrowband UVB spaced close together to improve their skin. Once the skin has
shown improvement, a maintenance treatment once each week may be all that is
necessary. However, narrowband UVB treatment is not without risk. It can cause
more severe and longer lasting burns than broadband treatment.
Psoralen and ultraviolet A phototherapy (PUVA). This treatment combines
oral or topical administration of a medicine called psoralen with exposure to
ultraviolet A (UVA) light. UVA has a long wavelength that penetrates deeper
into the skin than UVB. Psoralen makes the skin more sensitive to this light.
PUVA is normally used when more than 10 percent of the skin is affected or when
the disease interferes with a person's occupation (for example, when a teacher's
face or a salesperson's hands are involved). Compared with broadband UVB
treatment, PUVA treatment taken two to three times a week clears psoriasis
more consistenly and i fewer treatments. However, it is associated with more
short-term side effects, including nausea, headache, fatigue, burning, and
itching. Care must be taken to avoid sunlight after ingesting psoralen to avoid
severe sunburns, and the eyes must be protected for 1 to 2 days with UVA
absorbing glasses. Long-term treatment is associated with an increased risk of
squamous-cell and possibly, melanoma skin cancers. Simultaneous use of drugs
that suppress the immune system, such as cyclosporine, have little beneficial
effect and increase the risk of cancer.
Light therapy combined with other therapies. Studies have shown that
combining ultraviolet light treatment and a retinoid, like acitretin, adds to the
effectiveness of UV light for psoriasis. For this reason, if patients are not
responding to light therapy, retinoids may be added. UVB phototherapy, for
example, may be combined with retinoids and other treatments. One combined
therapy program, referred to as the Ingram regimen, involves a coal tar bath,
UVB phototherapy, and application of an anthralin-salicylic acid paste that is
left on the skin for 6 to 24 hours. A similar regimen, the Goeckerman treatment,
combines coal tar ointment with UVB phototherapy. Also, PUVA can be combined
with some oral medications (such as retinoids) to increase its effectiveness.
Topical Treatment
Systemic Treatment
Combination Therapy and Psychological Support
Promising areas of Psoriasis research
1 http://www.niams.nih.gov/Health_Info/Psoriasis/default.asp
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