Light Therapy

Have you noticed that during the summer, psoriasis generally gets better. Well it is not your imagination, since natural sunlight can help psoriasis. Living in the cloudy Pacific Northwest, I see more psoriasis than say when I lived in New Orleans . Currently there are three times of light therapy.

Broad band UVB

The Ultraviolet B spectrum runs from 280 to 320 nanometers. Previous light treatment use to give the full spectrum of UVB light. The benefit was that it did not require any medications before treatment. However with the advent of Narrow Band UVB, Broad band has been slowly phased out. However, you might still find some doctors who use broad band uvb

Narrow Band UVB

As we gained more experience with UVB therapy, researchers soon discovered that the spectrum of UVB from 311-313 nanometers was found to be the most efficacious in treating psoriasis. This discovery led to the development of new light bulbs that only emit light in that spectrum. Studies have shown that narrow band UVB is more efficacious than broad band UVB and this has become the standard of treatment in many clinics. IT is usually given between two to three times a week. The benefits are that there are generally no systemic ( internal) side effects with each treatment and it can be very effective for people with severe disease. The disadvantages are the time and inconvenience of treatment and the risk of sun burn. There is concern for risk of skin cancer and is a topic you should talk about with your doctor.


Many of you may have heard of a laser for the treatment of psoriasis. Many assume that you can laser away your psoriasis. While in some ways that is true, it is not the idea as when we destroy small blood vessels or hair follicles. It is not cures. Currently there are lasers known as the excimer laser that emits laser light in a similar frequency as narrow band light. In essence it is giving similar light found in narrow band UVB but at much higher concentrations. It is mainly used to target small tough areas that do not respond to conventional treatment. It is not appropriate to use the laser for large areas of psoriasis and still requires visits to your dermatologist two to three times a week as with narrow band UVB.

Psoralen with UVA (PUVA)

Until relatively recently, this was the gold standard in the treatment of psoriasis. This involved the ingestion of a medication that sensitized the skin to light known as psoriasis. This is a compound that can be found in low levels like lime. After ingestion, the patient is treated with UVA light. Initially this was found to be one of the most effective treatments for psoriasis. However over time it has become apparent that prolonged treatment can increase the risk of development of skin cancer. While it is still used, with the development of new therapies, it is slowing becoming less common