Also known as ultraviolet light therapy, UV light therapy, or UVB light therapy, phototherapy is a safe and effective treatment for a variety of skin conditions. Phototherapy uses light rays to make beneficial changes in skin cells. Unlike natural sunlight and tanning beds that present a risk of sun damage and skin cancer, phototherapy delivers a narrow band of ultraviolet (UV) light that minimizes these risks and delivers all the benefits of phototherapy.
Ultraviolet light therapy treats a number of skin conditions, such as psoriasis, eczema, vitiligo, and chronic itching.
Phototherapy harnesses the power of light rays, like those produced by the sun. Light rays move from the sun to the earth in waves, with some rays having longer waves than others. Light with longer wavelengths looks and behaves differently than light of shorter wavelengths; some wavelengths produce beneficial effects on the human body.
Scientists measure these waves of light in nanometers (nm). The visible spectrum of light, which is the light we can see, measures 400 to 700 nm. At 400 nm, light appears violet in color; at 650 nm, light rays are red. Ultraviolet light has shorter wavelengths than visible light, measuring 10 nm to 400 nm. While these light rays are invisible to the naked eye, exposure to UV light can have profound effects on skin cells.
Scientists divide UV light into three bands:
UVC is the most dangerous type of UV light; fortunately, the atmosphere stops UVC rays before they reach the Earth. UVA can penetrate into the skin to cause tanning, skin aging, and wrinkling. Medium-wave UVB is very biologically active, but it cannot penetrate beyond the superficial layers of skin.
Phototherapy delivers a concentrated dose of UVB light at a specific narrow band UVB wavelength (311 nm), which promotes beneficial changes in skin cells but also minimizes the risk of sun damage and skin cancer.
There are several types of light therapy, categorized according to the wavelengths of light they use. Each type of light therapy interacts with the body in its own way to provide unique benefits.
Red and near-infrared treatments use wavelengths between 635 nm and 940 nm. These wavelengths can penetrate the surface of the skin to reach cells in the skin and deeper. Once there, red and near-infrared light stimulates the production and transport of energy within the treated cells.
Blue light therapy uses wavelengths measuring 405 to 420 nm to kill the Propionibacterium acnes bacteria that cause acne.
Ultraviolet light therapy uses wavelengths measuring 10 nm to 400 nm. This therapy treats many conditions, such as atopic dermatitis.
UVB treatments are performed in-office, 2-3 times weekly on a regular schedule. The treatment lasts less than five minutes and requires no special preparation.
During the treatment, patients stand in a light unit that features swinging doors, which completely encircles the body. The treatment area is exposed so that the skin can absorb the UV light rays, but patients can otherwise remain dressed. Patients wear goggles to protect their eyes.
Phototherapy is painless – in fact, many patients find UVB light therapy warm, soothing, and comforting.
Most patients achieve their goals of relief from rash and itching or remission of the underlying condition in 6 to 8 weeks of therapy. Many patients benefit from repeating a UVB series on an as-needed basis to keep a condition under control or to maximize the benefits of phototherapy.
Light therapy offers a number of benefits, particularly for those who have certain skin conditions that may not respond to other conditions. As many as 31 million people in the United States have eczema, also known as atopic dermatitis, which causes uncomfortable itch and inflammation. Atopic dermatitis ultraviolet light therapy, also known as light therapy for eczema, helps reduce these symptoms without the need for messy creams or medications.
Light therapy benefits people with vitiligo too. In vitiligo, the skin loses its pigment cells, which causes discolored patches of skin. Skin doctors recommend light therapy for the treatment of vitiligo, as exposure to certain wavelengths of light triggers the production of pigment-producing cells in the skin. Many dermatologists recommend narrow-band UVB light therapy for vitiligo, as this wavelength of light minimizes the appearance of depigmented patches of skin associated with the condition.
Dermatologists also recommend UVB light therapy for psoriasis, a condition that causes red, itchy scaly patches that most commonly appear on the knees, trunk, elbows, and scalp.
Light therapy produces these benefits in a safe, comfortable, and effective manner. Many patients notice an improvement in their symptoms after the first light therapy session and continue to enjoy the benefits of light therapy as they continue their treatments.
For more information on light therapy, consult with your skin doctors at Center for Dermatology & Laser Surgery. Our team of skin care professionals can help you determine if UVB light therapy or other phototherapy approaches are right for you.