Light therapy, also called Phototherapy, uses natural or artificial ultraviolet light to help clear psoriasis. The goal of light therapy, or phototherapy, is to kill the active T cells in the skin causing the uncontrolled build up of skin cells, resulting in the condition we call psoriasis.
While light therapy can be an effective treatment, it does come with side effects that can be harmful – most notably, the sunburn effects from light therapy can be harmful to the skin. Your doctor will determine the best treatment plan for your condition. In the meantime, it’s important to understand the different types of light therapy available.
Different Light Sources and Treatments
Natural Light – natural sunlight is an effective treatment for psoriasis – one that has been prescribed for decades. When exposed to the UV rays of the sun, the activated T-cells in the skin die. Controlled daily exposure to the sun (no more than 20 minutes at a time) can help clear the condition in some people. Intense sun exposure can worsen symptoms and cause skin damage, so it is important to limit your time in the sun and protect the unaffected skin, face and hands (if not affected) with a sunscreen of SPF 15 or more before going outside.
UVB Phototherapy – also called broadband UVB, this treatment can be used to treat single patches of psoriasis, widespread psoriasis, and psoriasis that is resistant to tropical creams. Used in controlled doses, UVB light from an artificial source may improve mild to moderate symptoms of psoriasis. Broadband UVB therapy can produce sunburn from the short waves, so it does come with some risk. Other side effects include dry skin, redness and itching, but these are short term and can be helped with a moisturizer.
Narrowband UVB Therapy – narrowband UVB lamps emit light over a very short range, concentrating on the damaged areas of skin and minimizing the sunburn effects. It is therefore considered safer and more effective than UVB broadband therapy. Narrowband UVB therapy is a newer type of light therapy that is usually administered 2-3 times a week until the skin improves. After that, a single treatment each week to maintain the treatment is usually required.
Photochemotherapy – also called PUVA (Psoralen Plus Ultraviolet), this light therapy involves taking a light-sensitizing medication (Psoralen) before treatment. This allows the UVA light to penetrate deeper into the skin than broadband or narrowband UVA light, and it makes the skin more receptive to the UVA light. This light therapy is more aggressive and is usually reserved with those with severe cases of psoriasis.
Goeckerman Therapy – this uses UVB light therapy with a coal tar treatment. Coal tar is a thick brown liquid, made from coal. The coal tar makes the skin more receptive to the UVB light and it also works by slowing the overgrowth of skin cells and reducing inflammation, which improves itching and skin appearance.
Ingram Regimen – similar to the Goeckerman therapy, this uses UVB light therapy with a coal tar bath and a anthralin-salicylic paste that is left on the skin for several hours overnight.
Psoriasis is difficult to treat – a specific therapy that works for one, may not work for another, and light therapy is only one approach. Your doctor will determine the best approach for your condition. There are other treatments that do not include light therapy, such as natural treatments, and treatments you can do at home.
U.S. National Library of Medicine. National Institutes of Health. Psoriasis and Light Therapy at PubMed.gov
National Psoriasis Foundation. Light Therapy. 2008.