Phototherapy, also called light therapy, is a treatment that uses ultraviolet light from a medical device to relieve certain skin conditions. It can ease or get rid of itching, redness, and swelling in some adults and children who have moderate to severe atopic dermatitis.
Your dermatologist might recommend phototherapy for atopic dermatitis (also called eczema) if you have symptoms all over your body. They might also suggest it if you have symptoms on just a couple of body parts and you’re not getting relief from medications that you put on your skin.
It’s not for you if you have atopic dermatitis that’s mild. It’s also not for people who have a photoallergy disorder or a type of dermatitis that’s UV-sensitive.
How Can Phototherapy Ease Atopic Dermatitis?
When you’re living with this skin condition, your body’s defenses (the immune system) overreact to certain triggers in the environment, and they make too much inflammation in your skin. That’s what sets off your atopic dermatitis symptoms.
Natural sunlight gives off ultraviolet rays, which ease some people’s symptoms by turning down the inflammation process in the skin. But UV rays can also cause sunburns if you’re not careful. With phototherapy, your doctor exposes your skin to a certain dose of UV light for a precise amount of time. Experts say this lowers the inflammation that leads to atopic dermatitis symptoms.
Your dermatologist can treat your skin with one of two types of UV light: UVA or UVB. Or they can use a combination of both. They’ll choose the type of UV light and the dosage that’s most likely to be safe and effective for you.
Treatment with “narrowband” UVB light -- which gives off a shorter wavelength than “broadband” UVB light -- is the most common type of phototherapy that doctors use for atopic dermatitis. Limiting the light spectrum with narrowband UVB can lower your chances of having side effects.
To figure out the right treatment plan for you, your dermatologist will consider things like:
- The type of skin you have
- The type and number of past treatments you’ve gotten
- Whether you’ve had other health conditions, like skin cancer
- Whether you’re taking any meds that make your skin more sensitive to light, like antibiotics or NSAIDs
What Happens During a Phototherapy Session?
Most people go to a dermatology center or a hospital to get this treatment. Depending on the exact type of phototherapy you get, a typical session could involve these steps:
Right before your session, you’ll put moisturizing oil on the parts of your skin affected by atopic dermatitis. If you have symptoms all over your body, you’ll undress in privacy to apply the oil (keeping your undergarments on) and you’ll put protective goggles over your eyes.
If you’re getting UVA phototherapy, your dermatologist will also have you take a prescription medicine called psoralen before each session. You take it by mouth a couple of hours before the session, or rub a cream or gel version on your skin shortly before the session, depending on which form your doctor prescribes. Psoralen makes your skin more sensitive to UV light. It’s not safe to get UVA light therapy with psoralen if you’re pregnant or breastfeeding.
The phototherapy session itself usually involves going into a booth or chamber that gives off UV light. Or, if you have atopic dermatitis symptoms on just one or two body parts -- like your head, hands, or feet -- your dermatologist might simply have you place them under a special UV lamp.
The dermatologist usually exposes you to the UV light for seconds to minutes. They’ll decide the exact amount of time.
There are other types of phototherapy, including one kind that combines bathing and exposure to UV light. Another type involves getting tar applied to your atopic dermatitis patches to make them more sensitive to the light.
How Many Phototherapy Sessions Do You Need?
In general, you might need two to three sessions per week for a few weeks to months. As your treatment goes on, your itching may improve and your skin may slowly clear up.
Once your atopic dermatitis symptoms are gone or almost gone, your dermatologist will have you come in for phototherapy sessions less often before stopping them.
For the treatment to work best, you need to keep up with your sessions and go to them regularly.
What Are the Side Effects of Phototherapy?
It’s possible to have side effects like these:
Skin redness. It’s normal for this to show up within 24 hours of your phototherapy session. It’s usually mild and goes away quickly.
Sunburn-type reaction. If you notice this, call your dermatologist or treatment center. You’ll need to see your dermatologist to get it checked if it lasts for more than 24 hours.
Dry skin. This is common. You can ease it by moisturizing after your phototherapy session.
Premature skin aging. This can happen with long-term use of UV light therapy.
Acne-like breakout. Phototherapy could cause your skin to have this reaction.
Higher chance for skin cancer. Getting exposed to UV rays often can raise your risk, especially if you get UVA with psoralen. But some experts say the overall risk is low. Ask your doctor what the safe total dose of UV light is for you based on your health and risk factors.
Nausea. You could have this side effect if you take psoralen tablets. Your doctor may adjust your medication to try to prevent nausea. Taking your psoralen with food could also help. Eat the same amount of food each time you take a tablet.
Symptom flare-up. Sometimes atopic dermatitis acts up or becomes worse when you start getting phototherapy. Your dermatologist can usually manage the flare by adjusting your dose of UV light and giving you steroids and moisturizing treatments.
Eczema herpeticum infection. If you have the herpes simplex 1 virus, phototherapy for eczema might cause it to become active again. If that happens, your doctor can treat the infection with antiviral tablets. If you have a history of cold sores that get triggered by sunlight, tell your dermatologist, and wear sunblock during phototherapy sessions to help prevent problems.
Call your dermatologist if you have any phototherapy side effects that are painful or make you worry. Also call them if:
- The atopic dermatitis doesn’t gradually improve.
- It gets worse.
- You can’t keep up with phototherapy appointments.
What Other Safety Measures Should You Take?
While you get phototherapy for atopic dermatitis, it’s important to limit how much sun you get. Apply sunscreen with at least 30 SPF every 2 to 3 hours while you’re outside, and wear a wide-brimmed hat.
Don’t sunbathe or use a tanning bed. It could severely burn you. Using a tanning bed can also raise your chances for skin cancer.
How Can You Prepare a Younger Child for Phototherapy?
If your little one is scheduled to get phototherapy inside a UV light booth or unit, you could visit the unit together before their first treatment to help ease any fears they have. That way, they can see what it looks like and learn what to expect.
During their first session, you could stand by the unit and talk to them while they’re inside. Some units have a window that you can see each other through.
If there’s enough room in the phototherapy booth, some dermatologists even allow a parent to stay inside it with their child for the first few sessions until the child feels comfortable enough to be on their own. The parent stays fully clothed to protect their skin.