Light Therapy or Phototherapy

While light or sun-exposure can predispose patients to skin cancer, it is in fact a very useful tool in the dermatologist’s office to treat chronic skin conditions.

Phototherapy and sun-exposure will decrease immune cells in the skin called Langerhan cells. When patients have had a severe sunburn, they can actually feel quite sick for various reasons and even develop low-grade fevers; part of that is from immunosuppression. Phototherapy for chronic rashes works in a similar way by suppressing the local immunity in the skin, which is overactive in most conditions we treat with light therapy. Conditions such as psoriasis, chronic eczema, mycosis fungoides, (which is a lymphoma of the skin), vitiligo, (which is loss of pigment of the skin), are in large part due to the body’s immune system misfiring and attacking the skin or elements of the skin.

Phototherapy works to decrease the overactive immune system in the skin contributing to these conditions without sunburn and can be quite effective.

Phototherapy can be done with ultraviolet B alone and we use specialized so-called Narrowband ultraviolet B, which limits the exposure to a fairly narrow wavelength of light trying to maximize its benefit and minimize its toxicity. The toxicity from ultraviolet light is similar to sun exposure and includes increasing one’s risk for skin cancer and causing wrinkles and brown spots.

PUVA, which is short for Psoralen plus ultraviolet A, is a much more potent form of light or phototherapy. This is where patients apply a drug called Psoralen to affected areas or take a pill containing Psoralen prior to being exposed to ultraviolet A. Ultraviolet A transforms the drug Psoralen into a toxic compound, which can cause severe phototoxicity. Patients have died when given Psoralen inappropriately and told to go out into the sun resulting in horrific sunburns. Psoralen or PUVA therapy has to be strictly controlled by the dermatologist or specially-trained dermatologic physician assistant to monitor both the dose of Psoralen and the dose of ultraviolet light. Despite the risks, its effectiveness is quite remarkable for some of the chronic conditions listed above. In addition to sunburns, it can affect the eyes so any patient given Psoralen has to be seen by an ophthalmologist to make sure that the Psoralen combined with the light therapy does not damage the eye.

Psoralen taken orally can cause some side effects as can any drug; most often just mild nausea. Modern formulations of Psoralen have greatly minimized the nausea.

Patients who have terrible widespread skin diseases are in fact best managed by light therapy as we can apply therapy to the whole body simultaneously. In some instances, severe skin disease such as psoriasis or eczema is limited to the hands and feet and we have specialized phototherapy boxes that only expose the hands and feet to the light allowing us to treat only these areas and minimize toxicity. We also have the new Excimer laser to treat chronic psoriasis and vitiligo.

This new laser will work on areas that are often resistant to regular treatments. Some patients respond dramatically to the Excimer laser even after two or three treatments.

In summary, phototherapy is a wonderful tool to treat chronic widespread skin conditions such as psoriasis, eczema, vitiligo, and mycosis fungoides or lymphoma of the skin. These conditions can make patients miserable with itching in addition to causing red scaly skin. Widespread skin conditions go more than “skin deep”. Patients with terrible skin disease can shed so much protein and water from their skin that they can develop heart failure and kidney problems. Skin disease can be very serious and disabling and phototherapy is one of the many tools dermatologists have in their armamentarium to help patients. Solano Dermatology Associates is proud to offer these state of the art therapies to our patients in most of our offices.