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Light Therapy for Psoriasis

An NYU Langone dermatologist may recommend using light therapy as part of your treatment for psoriasis. Controlled exposure to strong ultraviolet light can help to reduce the number and size of psoriasis lesions and prevent new ones from forming.

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These treatments can be administered on-site at NYU Langone or in your home. Your doctor may recommend using topical or oral medications in combination with light therapy to relieve symptoms such as itching.

Solar Therapy

In solar therapy, also called heliotherapy, brief periods of exposure to natural sunlight help in clearing your skin. Dermatologists recommend first covering all areas of skin unaffected by psoriasis with a generous amount of broad-spectrum sunscreen with an SPF of 30 or higher. Applying a small amount of oil directly to the lesions helps the skin absorb more sunlight.

Initially, you spend up to 20 minutes in direct sunlight three times per week. Ultraviolet rays penetrate the areas of skin affected by psoriasis and may shrink lesions or cause them to shed. Under the guidance of a doctor, who may periodically examine your skin for sun damage, you may gradually increase the amount of time spent outside to a maximum of one hour.


Phototherapy uses ultraviolet light—the same type found in natural sunlight—that has been filtered to remove wavelengths that damage skin. Exposure to these altered ultraviolet rays, called ultraviolet B (UVB) rays, may reduce skin inflammation, slow skin cell growth, and minimize the appearance of psoriasis lesions.

NYU Langone has a phototherapy center that offers full-body phototherapy in as little as 5 to 10 minutes. Each phototherapy room has dozens of long, tube-shaped light bulbs that emit UVB light. While you remain standing, light emitted from these bulbs penetrates your skin. Our specialists typically use narrow-band UVB bulbs, which emit an even more focused light wavelength to enhance effectiveness and reduce side effects such as redness.

Depending on the type of lesions you have and how much of your body is affected, dermatologists recommend having phototherapy up to three times a week. NYU Langone offers phototherapy appointments throughout the week, including evenings and Saturdays, to make treatment convenient.

If traveling to a doctor’s office that provides phototherapy is inconvenient for you, our dermatologists can give you information on a portable phototherapy unit that you can use at home.

Excimer Laser Treatment

Your dermatologist may recommend laser treatment if your symptoms don’t respond to topical medication, solar therapy, or phototherapy.

In this procedure, a dermatologist shrinks psoriasis lesions using an excimer laser, a highly concentrated beam of ultraviolet light that has been filtered to remove wavelengths that damage skin, allowing through the focused therapeutic UVB rays. Dermatologists target psoriasis lesions using a wand-like device. The UVB light reduces skin inflammation, slows skin cell growth, and lowers the number of lesions.

This procedure is painless and can be performed in your doctor’s office in less than a half hour. Multiple sessions are usually required, and dermatologists may suggest two or three sessions per week. Some people notice results after just a few sessions, and some see significantly clearer skin in about six weeks. Your dermatologist determines whether continued treatment is needed to maintain symptom relief.

You can expect to be able to return to work or continue your daily activities after treatment.

Our Research and Education in Psoriasis

Learn more about our research and professional education opportunities.