In phototherapy, skin is exposed to an ultraviolet (UV) light source for a set amount of time. It is used to treat certain skin conditions. UV lights are rays of light from the sun that are not visible. Phototherapy uses a man-made source of UV light for treatment.
Reasons for Procedure
Skin conditions that are treated with phototherapy include:
- Psoriasis—a skin disorder that causes red, silvery, scaly patches on the skin
- Atopic dermatitis—eczema (itchy, red skin condition) or dermatitis due to allergies
- Mycosis fugoides (cutaneous T-cell lymphoma)—a type of lymphoma confined to the skin
- Vitiligo—a skin disorder where normal skin pigment is lost due to destruction of pigment-producing cells by the immune system
The UV lights may negatively affect your skin in a number of ways, including:
- Skin conditions could temporarily worsen
- Itchy skin
- Red skin due to exposure to the lights
- Burning of the skin
PUVA treatment specifically may cause:
- Nausea (if you took the psoralen pills)
- Burning skin
- Cataracts (lens of eye becomes cloudy, affecting vision)
If you have received a great number of phototherapy treatments, you may be at risk for:
- Premature aging of the skin, such as wrinkling and dryness
- Age spots or freckles may appear
Factors that may increase the risk of complications include:
What to Expect
Prior to Procedure
You will be asked to remove any clothes covering the areas that need treatment. Areas that will not be treated should be covered and protected as much as possible.
- Use sunscreen to protect your neck, lips, and the backs of your hands.
- Protect your eyes by wearing special glasses or goggles. They will protect your eyes from UV light.
- Men need to cover their genitals. Women should apply sunscreen to their nipples and areola (the colored area around the nipple).
Make sure to inform your doctor about any medicine that you are currently taking. Some medicines, including over-the-counter medicine, increase the risk of side effects.
Description of the Procedure
Types of phototherapy include:
- Broad band UVB—This is effective light therapy treatment using UVB light (UV light, type B). It cannot be used in areas where there are skin folds.
- Narrow band UVB (nbUVB)—It emits a narrower range of UVB wavelengths. It can reach more specific areas, even skin folds.
- PUVA—This treatment involves taking or using a medicine called psoralen. This medicine makes your skin more sensitive to the UV light. Psoralen can be taken as a pill or applied to the skin.
- Lasers—An excimer laser emits a UV light. It is more narrow than the narrow band UVB lights. It can be directed at specific areas of the skin. Excimer laser is a newer procedure.
For any treatment, except laser, you will be asked to stand in a treatment unit. The unit is called a light box. It is lined with UV lights. Sometimes smaller units for treating smaller areas of your skin may be used.
For treatment with an excimer laser, a beam of laser light will be focused directly on the affected area of your skin. Treatments last less than five minutes.
How Long Will It Take?
The first treatment is usually very short, even a few seconds. Your phototherapy sessions will vary in length. It will depend on your skin type and the strength of the light chosen by your doctor. Treatments are typically just a few minutes.
Treatment for skin conditions generally requires several treatments each week. It takes approximately 10 weeks to complete the full treatment.
- Broad band therapy requires approximately 3-5 treatments each week.
- Narrow band therapy requires fewer treatments (2-3 treatments) each week.
- PUVA treatments generally require about 25 treatments over a 2-3 month period.
- Laser treatments are usually given twice a week and fewer sessions are required to clear the skin.
Treatments will continue until your skin is clear. Sometimes, occasional maintenance treatments are needed. The maintenance sessions can usually be done right in your doctor’s office, or even with a home UV light unit.
Will It Hurt?
You may feel a warm sensation on your skin, similar to a mild sunburn.
It is important to avoid natural sunlight when you are receiving UV light treatment:
- Clothing and sunscreen should be used when outdoors. They will help you avoid overexposure to UV light.
- There is an even bigger risk of sunburn after PUVA treatment. This is due to increased sensitivity from the psoralen.
- It is important to protect your eyes from sunlight exposure for the next 24 hours. This will help you to avoid cataracts, a clouding of the eye, after PUVA treatment.
- Your doctor should regularly examine your skin for skin cancer: UV light exposure from sunlight causes skin cancer. Long term PUVA treatment can increase the risk of skin cancer. No studies have found a direct link from nb UVB phototherapy to skin cancer.
- Antihistamines and other medicine may be given to ease the itching.
Be sure to follow your doctor's instructions.
Call Your Doctor
After arriving home, contact your doctor if any of the following occurs:
- Signs of infection, including fever and chills
- Redness around the skin lesions or any discharge
- Severe skin burning, pain, or blistering
- Side effects you experienced due to the treatment continue or worsen
- Development of new or surprising symptoms
In case of an emergency, CALL 911.
American Academy of Dermatology
National Psoriasis Foundation
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Phototherapy: lasers. National Psoriasis Foundation website. Available at: http://www.psoriasis.org/treatment/psoriasis/phototherapy/lasers.php. Accessed August 23, 2005.
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Last reviewed November 2009 by Ross Zeltser, MD, FAAD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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