What Is Phototherapy?

When antihistamines and other treatments do not ease chronic hives, you may look to alternative therapies. Many people use phototherapy, also called light therapy, to treat skin conditions like psoriasis. Researchers are still studying whether phototherapy improves chronic hives.

Before using phototherapy, you first need to try medicines applied to the skin (topicals). If they do not work, your doctor will refer you to a dermatologist. The dermatologist can help you figure out if phototherapy is right for you. They may recommend phototherapy or ultraviolet (UV) light to treat your skin.

How does phototherapy work?

UVA and UVB wavelengths from the sun penetrate the Earth’s atmosphere and help your body make vitamin D. Too much UV light can tan and burn the skin.

There are 3 kinds of phototherapy used to treat skin conditions – broadband UVB, narrowband UVB, and UVA. Researchers have studied narrowband UVB as a treatment for chronic hives.^1-4

Phototherapy eases inflamed skin. You could start to see the effects after several weeks of treatment. A nurse or other health professional trained in light therapy manages the treatments. There are also at-home phototherapy units. But before using an at-home unit, you will need a prescription from your healthcare provider.^1,2

You will start with 2 to 3 treatments a week. As your skin begins to improve, you will need fewer treatments. Still, you should continue your light therapy sessions to see the full benefits.¹

Does phototherapy help treat chronic hives?

Over-the-counter antihistamines are the usual treatment for chronic hives. If these antihistamines do not help, your dermatologist may suggest other treatments, like prescription drugs.⁵

If you are looking for a non-invasive treatment, light therapy is 1 option. There is not much solid scientific evidence to show how well light therapy works. A few small studies suggest that narrowband UVB phototherapy may be a good secondary treatment for chronic hives. Researchers will need to do larger studies and follow people with chronic hives for longer to confirm the results.^3,4

What are the side effects of phototherapy?

You may have sunburn-like redness and burning in the first 24 hours after getting phototherapy. This is normal and usually goes away quickly. If redness lasts longer than 24 hours, contact your doctor or dermatologist.¹

You and your phototherapy provider can help prevent this side effect by testing your light sensitivity. This test involves:¹

• Starting with a lower light level
• Noting any side effects
• Working your way up to a higher dose

Other side effects of light therapy may include:^1,2

• Dry skin
• Nausea from psoralen tablets (which you take to make your skin more sensitive to the light)
• Signs that your skin is aging, like wrinkles
• An increased risk of skin cancer

Skin protection is even more important when you are being treated with light therapy. Avoid unnecessary sun exposure. Wear sunscreen that is labeled SPF 25 or higher. When you are outdoors, reapply sunscreen every 2 to 3 hours. Also, do not use tanning beds while receiving light therapy. They supply too much UV light and can burn your skin.