Risks and Benefits of Light Therapy for Atopic Dermatitis

Light therapy, also known as phototherapy, is a skin treatment that harnesses the power of ultraviolet (UV) light to treat several skin conditions, which includes severe eczema. 

Light therapy can be a helpful treatment for people with difficult-to-treat atopic dermatitis, the most common type of eczema. But while light therapy can help improve symptoms, it also comes with risks.

Here's what you should know about the benefits and risks of light therapy for treating atopic dermatitis.

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What Are Eczema and Atopic Dermatitis?

Eczema is a widespread skin condition that affects nearly 31.6 million people in the United States. However, eczema is not a single condition but a grouping of many skin conditions involving chronic, itchy skin rashes. In general, many people with eczema develop dry, itchy, red patches of skin.

People with eczema often have a compromised skin barrier that dries out quickly and is more open to invasion from allergens, irritants, and germs. Also, people with eczema may have an overly sensitive immune system.

Atopic dermatitis is the most common form of eczema. People with atopic dermatitis often experience dry, scaly, red, and itchy patches on the face, scalp, hands, or feet; inside the elbows; or behind the knees. Atopic dermatitis tends to run in families and has a genetic component.

Symptoms of atopic dermatitis include:

• Red, itchy patches of skin on light skin; dark brown, purple, or ashen gray on dark skin
• Dry and scaly skin
• Areas of thickened skin
• Open, oozing, and crusty sores

People with atopic dermatitis can use several treatments and strategies to relieve symptoms, reduce inflammation, and prevent flares, which include:

• Topical ointments and creams
• Oral antibiotics or antihistamines
• Injectable medication
• Skincare treatments

Unfortunately, no single strategy works for everyone. And some people do not respond to those treatments.

What Does Light Therapy Treat?

Light therapy involves using different wavelengths of UV light. The therapy has anti-inflammatory, immunosuppressive, and cytotoxic effects. Light therapy is an effective treatment for several diseases, including neonatal jaundice.

Light therapy is mainly used to treat various skin conditions. Healthcare providers may prescribe the treatment to treat eczema and help reduce itch and inflammation.

How Does Light Therapy Treat Atopic Dermatitis?

Light therapy involves emitting UV light from special medical therapy lamps for atopic dermatitis to help reduce inflammation and itching.

Treatment with light therapy involves either ultraviolet B (UVB) or ultraviolet A (UVA) light. Narrowband UVB light is usually recommended for treating atopic dermatitis. But there are also other types, such as UVA1 and broadband UVB phototherapy.

After several weeks of regular treatments, about two to three times per week, the skin gradually improves and itching decreases. Once the skin is clear or almost clear, and the itching has stopped, the treatment frequency is reduced. For treatment success, the individual must attend all treatment sessions regularly.

"Some may say [light therapy] is time-consuming because it includes many treatments and visits to the [healthcare provider]. But its results are unrivaled," Kim Nichols, MD, a dermatologist and cosmetic surgeon in Greenwich, Conn., told Health. "A successful response returns the skin to a normal appearance."

Risks of Light Therapy

As with UV radiation from the sun, light therapy comes with risks. Some of the risks of light therapy include the following:

• Skin cancer: Exposure to UV radiation can produce genetic mutations that may lead to skin cancer. UV radiation also increases the risk of melanoma, the deadliest form of skin cancer. 
• Premature aging: Fine lines and wrinkles are especially common in fair-skinned people.
• Eye damage: People also wear goggles during light therapy sessions to protect against eye damage, such as cataracts.

Luckily, dermatologists are mindful of those risks. So, light therapy for atopic dermatitis is given in controlled doses, generally under the supervision of a healthcare provider. 

A healthcare provider will advise you on the total safe dose of UV light based on your condition and risk factors. 

Side Effects of Light Therapy

Some of the possible side effects of phototherapy include:

• Sunburn and skin tenderness: Some people will experience mild redness within 24 hours of treatment. Typically, redness fades quickly and is not uncomfortable. But if you experience a sunburn-type reaction, it is essential to contact a healthcare provider.
• Dry skin: Skin dryness is also a common side effect, so it is important to use moisturizer after each round of light therapy.
• Atopic dermatitis flare: For some people, symptoms of atopic dermatitis flare at the beginning of light therapy. You can usually manage this with topical corticosteroids and moisturizers, as well as by adjusting the dose of UV light.
• Eczema herpeticum: Light therapy can sometimes trigger the reactivation of eczema infected with the herpes simplex virus, also known as eczema herpeticum. A healthcare provider may prescribe antiviral tablets like aciclovir in those cases. Anyone with a history of cold sores triggered by sunlight should routinely wear sunscreen while receiving light therapy to prevent any reoccurrence.
  

What To Do After Light Therapy Treatment

Between rounds of light therapy, avoiding direct sunlight and sunbathing for several days after treatment is essential.

Also, applying a broad-spectrum, water-resistant sunscreen with an SPF of 50 or higher every two to three hours while outside is necessary. You can also wear a hat or long-sleeved shirt outside.

Who Should Try Light Therapy?

About 70% of people with eczema see an improvement in symptoms after light therapy.

Light therapy is generally reserved for adults and adolescents with widespread eczema symptoms. Also, those with atopic dermatitis who do not respond to first-line treatments, such as gentle moisturizers or topical steroids, receive light therapy.

Still, light therapy is not a cure-all for every person with eczema. And experts stressed that people with atopic dermatitis should speak to their healthcare provider about the benefits and risks of the treatment before trying it.

"We don't necessarily like to put people into it unless there's nothing else that's keeping them controlled," Jon Hanifin, MD, professor of dermatology at Oregon Health & Science University in Portland, Ore., told Health.

For those people, Dr. Hanifin described using an immunosuppressant medication, such as cyclosporine, for a limited time until their skin isn't "all thickened and red and scratched." 

Dr. Hanifin then recommended tapering off the treatment while building up their UV treatments to stop inflammation. Dr. Hanifin explained that light therapy could be a bridge to healthier skin for those people. 

"UV is really good for [some people]," said Dr. Hanifin. "But it's not for everybody."

Who Should Avoid Light Therapy?

People with UV-sensitive dermatitis or a photoallergy disorder should not use light therapy. People with those types of eczema may receive apt treatment at specialist clinics.

Additionally, light therapy with UVA light should not be used during pregnancy or breastfeeding. In contrast, light therapy with UVB light is generally safe during pregnancy and breastfeeding.

Questions To Ask a Healthcare Provider About Light Therapy

A healthcare provider should fully educate you about light therapy's benefits and risks for your eczema. Some of the questions you may want to ask a healthcare provider might include the following:

• Is light therapy right for me?
• What other treatments are available?
• What are the risks of light therapy?
• How long does it take for light therapy to work?
• How can I tell if my atopic dermatitis is getting worse or better?
• What are the post-light therapy instructions?
• When do we need to have a follow-up visit?
  

A Quick Review

Light therapy helps alleviate symptoms of several skin conditions, such as atopic dermatitis. The therapy might be part of the treatment plan that a healthcare provider prescribes for you.

Most people who undergo light therapy experience relief of symptoms and few side effects. However, there are risks, precautions, and potential adverse side effects. Ensure you follow a healthcare provider's instructions and safety guidelines if you use light therapy.