PUVA Therapy (Photochemotherapy)

  • Medical Author:
    Gary W. Cole, MD, FAAD

    Dr. Cole is board certified in dermatology. He obtained his BA degree in bacteriology, his MA degree in microbiology, and his MD at the University of California, Los Angeles. He trained in dermatology at the University of Oregon, where he completed his residency.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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What are the advantages and disadvantages of PUVA?

The major advantage to PUVA is that it is an effective therapy that becomes active only at the site of the disease, the skin. It can be used to treat large areas of skin, and the fact that the drug is only activated in the presence of UV light implies that it may be less toxic than other therapies that require systemic administration and whose effects are not localized to just the skin.

PUVA must be administered in a physician's office under the control of a medical professional so it requires repeated visits to the office. PUVA does not cure psoriasis so treatment may be required indefinitely.

How is PUVA therapy administered?

The psoralen medication is taken 45-60 minutes prior to the ultraviolet light exposure. The amount of the psoralen is based on the weight of the patient. The length of the exposure depends on the degree of the patient's pigmentation. Accordingly, the darker the patient, the longer the exposure time. Depending on the equipment used, the exposure may occur in a metal light box surrounding the patient with the bulbs that run vertically and are generally 48 inches long and resemble fluorescent bulbs. In newer boxes, there is an integrated light meter that enables the operator to administer the desired amount of energy with an automatic shut off after that dosage of light is administered.

How many PUVA treatments are necessary?

There ought to be a significant improvement in the patient's skin disease after about 15 treatments. Treatments are given no sooner than 48 hours apart because the burn (if there is one) induced by PUVA is often delayed for as long as two days (unlike ordinary sunburns). Unless there is a problem, the amount of energy administered to the patient is increased appropriately at each visit depending on the patient's coloration. After about 30 treatments, a decision is made as to whether to continue treatments. PUVA is not always effective. If there is no improvement after these treatments, it is probably unlikely that continuing this form of treatment is worthwhile. On the other hand, if significant clearing has occurred, it is probably prudent to decrease the frequency of treatments in order to maintain the improvement. Since there is a relationship between the amount of light energy administered and the degree of photo-aging and the induction of skin cancers, it is wise to limit the light exposures as appropriate.

Medically Reviewed by a Doctor on 6/9/2015

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