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| What is (P)UVA? |
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PUVA, also called "Phototherapy" is an acronym for psoralen (a light-sensitizing medication) combined with exposure to ultraviolet light A (with a wavelength between 320 and 400 nanometer). By itself, however, UVA is not usually used to clear psoriasis. It is relatively ineffective unless used with a light-sensitizing medication such as psoralen. PUVA can also refer to treatment with ultraviolet light B, which does not need extra medication to be effective. UVA, like UVB, is found in sunlight. PUVA therapy is a common treatment for various forms of psoriasis, because it slows down two processes that are associated with psoriasis:
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| How is UVA administered? |
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The positive effect of sunlight on Psoriasis has been known for a long time. Sunlight is more than the light that we can see. It also contains non visible, Ultraviolet rays like UVA and UVB. PUVA therapy uses these UV radiation. PUVA treatments take place in a doctor's office. After psoralen is ingested or applied to the skin, a patient exposes his or her psoriasis lesions to UVA in a light unit lined with ultraviolet lamps. Most UVA units are vertical, and patients stand during treatment. Other special UVA units are used for exposing only specific parts of the body, such as the hands and feet. A doctor and his or her phototherapy staff know exactly how much time should elapse between the patient taking the pill or applying psoralen topically, and exposing the lesions to UVA. Timing is critical to the success of the treatment. For the UVA light exposure to work, it must be administered at a time when the psoralen is at a high level in the skin. Oral PUVA is the most common form. It calls for the patient to take psoralen pills 75 to 120 minutes before entering the PUVA Cabin. Initially, exposure to UVA may be very short (30 seconds to several minutes), depending on the patient's skin type and the kind of UVA unit. Exposure time is gradually increased to 20 minutes or longer, depending on the strength of the UVA light. On average, 25 treatments are required for clearance, but may be greater for very severe psoriasis. Some doctors conduct a test treatment on a small area of the skin to test the sensitivity of the skin to UV radiation. The results will determine the start dose for the particular patient. Mostly the treatment schedule is based on the skin type of the patient.
Lower skintypes demand precaution, lower radiation times with gradually small increases. For the higher skintypes, the first sessions can be much longer and radiation can be increased faster. After clearing, a person may or may not go on a maintenance regimen, depending on the aggressiveness of the psoriasis. Only one or two PUVA treatments per month may be needed to maintain clearance, although the exact regimen will vary for each patient. |
| What is a UVA cabin? |
A PUVA cabin can be compared with a sun booth (a vertical tanning bed) equipped with special UVA and/or UVB tubes. Compared to a sun booth, there are a few differences with a PUVA cabin.
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| How effective is UVA? |
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PUVA is a very effective treatment for psoriasis. Studies show that PUVA clears psoriasis for more than 85% of patients. It induces long remission times, even without maintenance treatment, that can last from a few months to more than a year. To reach this result, treatment should take place 2-3 times a week for 6-10 weeks. |
| What are the side effects of UVA? |
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The most common short-term side effects of oral UVA are nausea, itching and redness of the skin. Drinking milk or ginger ale, taking ginger supplements or eating while taking oral psoralen may prevent nausea. Antihistamines, baths with colloidal oatmeal products or application of topical products with capsaicin (an extract of hot peppers) may help relieve itching caused by PUVA. Swelling of the legs from standing during PUVA treatment can sometimes be relieved by wearing support hose. Skin cancers The primary long-term risk of PUVA treatment is a higher risk of skin cancer, particularly non-aggressive forms like squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). Studies show the more PUVA treatments you have, the more at risk you are for developing skin cancers, compared to the general, non-PUVA-treated population. Long-term PUVA treatment requires careful monitoring for skin cancer, even after treatments are finished. If you have had more than a total of 150 PUVA treatments, it is advisable to have an annual skin examination by a dermatologist. Skin cancers generally can be removed easily if detected early. Early signs of an increased risk of non-melanoma skin cancer are keratoses, or raised, scaly wart-like bumps, that can range from a tenth- to a half-inch in diameter at the base. PUVA-induced keratoses (as opposed to sun-induced keratoses) tend to appear on skin that does not receive regular sun exposure (e.g., the trunk and thighs). Keratoses and early skin cancer lesions generally can be removed. Cataracts There is a potential for PUVA to induce cataracts if the eyes are not protected for 12 to 24 hours after a PUVA treatment. Psoralen remains in the eye lens for a period of time following ingestion of the drug. To date, no increase in cataracts has been noted in patients using proper eye protection. Use of commercial sunglasses should be discussed with your doctor. Sunglasses must filter out 100 percent of the ultraviolet light. Freckling and skin aging PUVA patients who have received more than 150 treatments within five years are at a higher risk for premature aging of the skin. The aging usually takes the form of wrinkling and dryness, or tight, shiny skin. Discolored spots that look like dark freckles may develop. |
| Who is a candidate for UVA? |
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PUVA is considered for moderate to severe cases of psoriasis in adults. Stable plaque psoriasis, guttate psoriasis, and psoriasis of the palms and soles are especially responsive to PUVA treatments. PUVA is not normally recommended for children or teenagers. However, it can be used by young people to avoid unwanted side effects of other treatments or if other treatments have not been successful. Some people are not good candidates for PUVA due to their medical histories. The following are possible reasons to avoid PUVA:
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| What is UVB? |
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Present in natural sunlight, ultraviolet light B (UVB) is an effective treatment for psoriasis. UVB penetrates the skin and slows the abnormally rapid growth of skin cells associated with psoriasis. UVB treatment involves exposing the skin to an artificial UVB light source for a set length of time on a regular schedule, either under a doctor's direction in a medical setting or with a home unit purchased with a doctor's prescription. Although the cabin is equipped with UVA/UVB tubes or UVB tubes only, It is still called a PUVA cabin. There are two types of UVB treatment, broad band and narrow band. Broad-band UVB is more commonly used in the United States; however, narrow-band UVB is similar in many ways and is becoming more widely used. 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 faster and produces longer remissions than broad-band UVB. Narrow-band UVB may be effective with fewer treatments per week than broad-band UVB. The use of narrow-band UVB increases as doctors and patients learn more about its effectiveness and safety and as the equipment becomes less expensive. |
| How is UVB administered? |
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The patient stands in a PUVA cabin with UVB lamps, or an enclosure containing one or more columns of lamps. A person undresses to expose all affected areas to the ultraviolet light. Some doctors have small units for treating localized areas such as the palms and soles. A patient generally will receive treatments three times per week. It takes an average of 30 treatments to reach maximum improvement of psoriasis lesions. The first exposure to the light is usually quite short, lasting as little as a few seconds. Exposure time depends on the person's skin type and the intensity of the light emitted from the bulbs. People with lighter skin start with shorter exposure times than people with darker skin. Normally, treatment times are gradually increased until clearing occurs, unless the last session produced itching and/or skin tenderness. Because administering UVB light is not an exact science, each person's reaction to the light is not completely predictable. Subsequent sessions of UVB are adjusted according to a person's individual response. UVB requires a significant time commitment. People get the best results when they keep scheduled appointments and follow treatment directions carefully. A doctor may require a patient to do one or more of the following before UVB treatments begin:
Once the skin clears, the treatments can be stopped. They should be resumed as the lesions begin to reappear. Sometimes UVB is continued on a maintenance basis. Studies show that UVB maintenance can increase remission time. Most people need about eight maintenance treatments per month to prolong clearance, but it is different for every person. If psoriasis lesions return, an individual may return to three treatments per week. Sometimes a person is rotated to a different psoriasis treatment. This rotation gives the skin a break from UVB, minimizing long-term exposure and possible side effects. |
| What is a UVB cabin? |
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Although the term PUVA is technically not applicable for UVB treatment because no Psoralen are used and the UVA light is replaced by UVB. It is common for patients to receive UVA as well as UVB radiation during the same treatment. The amount of joules for each wavelength is programmed and lamps will start and stop when the dose is reached. Therefore, in everyday use, PUVA cabin or PUVA therapy is used to refer to a cabin or treatment with UVA as well as UVB light. A PUVA cabin can be compared with a sun booth (a vertical tanning bed) equipped with special UVA and/or UVB tubes. Compared to a sun booth, there are a few differences with a PUVA cabin.
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| How effective is UVB? |
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Studies for response rates to Narrow Band-UVB shows that more than 55% of the patients had a complete response, 30% had a partial response and only 15% of the patients had no response at all. To get these results, patients need to be treated according a tight treatment schedule during several weeks. Overall it can be said that NB-UVB has an effectiveness of 85% and is a useful, safe, and easily administered way for treating psoriasis. |
| What are the side effects of UVB? |
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During treatment, psoriasis may worsen temporarily before improving. The skin may itch and become red because of exposure to the UVB light. The amount of UVB administered may need to be reduced to avoid further irritation. Occasionally, temporary flares occur even with non-burning doses of UVB. These reactions may resolve with continued UVB treatment. Sunburn Certain medications, herbal supplements and topical ingredients can cause sensitivity to light; it is important to tell your doctor about all medications, treatments and supplements you are taking. Patients should avoid exposure to natural sunlight on UVB treatment days. Overexposure to ultraviolet light can cause a serious burn. Skin cancer UVB is an established carcinogen (cancer-causing substance or agent) in humans. However, there is no direct evidence of increased risk of skin cancer from UVB treatment for psoriasis. It is important to have a doctor examine your skin periodically. Skin cancers generally can be removed easily if detected early. Some doctors recommend the use of sunscreen on uninvolved skin as a means of minimizing exposure to UVB. The face, for example, is exposed to a great deal of natural sunlight. If there is no psoriasis on the face, a person should avoid UVB exposure there. |
| Who is a candidate for UVB? |
UVB treatment can be used by adults and children, and will be effective in treating psoriasis for at least two-thirds of patients who meet these criteria:
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