If you or a loved one have the skin condition known as eczema, the summer poses some unique challenges. For starters, is the sun good (or bad) for eczema symptoms? While some swear by the sun’s rays to help mitigate side effects that come with atopic dermatitis, others avoid those blinding rays at all costs. And while some doctors prescribe light therapy to eczema patients, others are apprehensive about it since improper sun exposure can lead to sunburn and sun damage that may actually trigger an eczema flare-up.

Overall, though, research suggests that most people with eczema believe the sun helps their skin: In a study published in the Italian Journal of Dermatology and Venereology, approximately 59% of patients said that sunlight was beneficial for their skin, and 33% specifically reported improvement of their eczema.

So, is it a good idea to catch some rays to clear your skin? Possibly—if you don’t overdo it, you don’t have photosensitive eczema (a type that is triggered by UV light), and your doctor is on board. What else should you know? Before your next sun day, consider this advice from eczema experts.

Eczema and Vitamin D

The prevailing theory as to why exposure to the sun may benefit some people with eczema mostly boils down to its ability to increase the body’s production of vitamin D. “There is evidence that vitamin D can help treat eczema, as lower serum levels of vitamin D are associated with a higher incidence and more severe eczema symptoms,” says Jaimie DeRose, M.D., an assistant professor at Boston University School of Medicine and Harvard Medical School in Boston, MA.

The relationship between eczema and vitamin D is not crystal clear, but research has revealed a few possible explanations: Vitamin D triggers the release of cathelicidin, an amino acid compound that is typically low in eczema patients. Cathelicidin is a part of our body’s natural defense system and researchers believe it helps bolter the immune response to protect the skin. There’s also evidence that vitamin D plays a role in immune system regulation, which may help prevent an excessive immune response that can lead to chronic inflammation.

And finally, the vitamin has anti-inflammatory properties. “Vitamin D plays a role in decreasing inflammation and helping to maintain a healthy skin barrier, both of which are important for maintaining healthy skin,” says Rebecca Marcus, M.D., a board-certified dermatologist at North Dallas Dermatology in Dallas, TX. That’s especially noteworthy, as eczema is considered a chronic inflammatory skin disease.

Sunlight and Eczema Prevention

The lower vitamin D levels seen in eczema patients invites a bit of a chicken-or-egg question: Could higher levels of vitamin D help prevent eczema from developing in the first place?

There’s some evidence this could be the case—and that sunlight is the key rather than just vitamin D itself. In a study on infants in The Journal of Allergy and Clinical Immunology, six-month-old babies given vitamin D supplements had no difference in eczema occurrence from those who did not receive the supplement. Yet those who received an increased amount of UV exposure had lower incidence of eczema and proinflammatory immune markers (like cytokines and certain immune cells that indicate the presence of inflammation) than children who were not exposed to UV rays. However, as this was the first study to look at this link, more research is needed.

Sunlight vs. Phototherapy for Eczema

While sunlight may help tame symptoms of eczema, doctors say to exercise caution. “The first line treatment for atopic dermatitis is topical or systemic anti-inflammatory treatments as well as proper skincare,” says Dr. DeRose. Because of the melanoma risks that come with the sun’s rays, she says, UV light therapy should always be a secondary line of treatment, which your doctor may advise if the other strategies aren’t controlling your symptoms.

Similar to sunlight therapy is phototherapy, in which artificial light is used to treat eczema symptoms. According to the National Eczema Society, the most common type of phototherapy used to treat eczema is narrowband ultraviolet B (NB-UVB) light, though others like ultraviolet A (UVA) light are also used.A research review published in the Indian Journal of Dermatology, Venereology, and Leprology concluded that evidence suggests phototherapy can help reduce eczema severity.

Although it might be less convenient to travel to your doctor’s office rather than sit out in your backyard, Dr. Marcus prefers phototherapy over sunlight for her patients. “Wavelengths of UVB light can help decrease inflammation and symptoms such as itching while also minimizing the side effects and risks that come along with exposure to sunlight and a broader spectrum of UV radiation,” she says. Sunlight, on the other hand, “is made up of a much broader spectrum of UVA, UVB and UVC, and therefore exposes the skin to risks and negative effects of the entire range.”

What to expect? Before setting your skin before a phototherapy lamp, you’ll put on special gear. “Your doctor will have you wear protective gear, such as eye protection and sunscreen to protect the areas not treated,” says Dr. DeRosa. Afterwards, she suggests avoiding the sun and being generous with sunscreen in between sessions to prevent excessive drying and more damage that could contribute to itching and flares. Phototherapy results don’t happen overnight: According to research in Dermatology and Therapy, patients with moderate-to-severe psoriasis require 20–36 sessions of phototherapy done three times per week to see a significant improvement.

Can Sun Make Eczema Worse?

It could. That’s because, as Dr. Marcus explains, “too much sun can cause sunburn, which increases inflammation in the skin, as well as raises risk of skin cancer and photoaging.” Beyond the direct impact of the rays, Dr. DeRosa also points out that “increased sweating outside in sunshine can irritate eczematous skin and worsen a flare-up.”

While rare (there’s currently no data of incidence), there are also those with photosensitive eczema in which sunlight exposure literally triggers an outbreak. If you think you have photosensitive eczema, it’s best to avoid the sun as much as possible and consult with a dermatologist for treatment options.

What Is the Ideal Amount of Sun Exposure for Eczema?

There’s no real answer as to how much sunlight a person should get to relieve their eczema symptoms. Since everyone has different sensitivity levels, Dr. Marcus says your doctor should guide your treatment when it comes to any type of phototherapy. But no matter how long you decide to spend in the sun, the National Eczema Society advises people with eczema to follow the sun safety tips below.

Eczema Sun Safety Tips

This quick checklist from the National Eczema Society can help keep you safe in the sun:

• Wear accessories and clothes that cover vulnerable body parts like a hat, T-shirt, and sunglasses.
• Head to the shade between 11 a.m. and 3 p.m., when the sun’s rays are strongest.
• Use a sunscreen with SPF 30 or higher (general advice: reapply every two hours when outdoors).
• Make sure you apply sunscreen generously (think about an ounce of sunscreen per application) and frequently when in the sun.

Additionally, it’s always important to avoid anything you’ve identified as a trigger, such as tight clothing or sunscreen formulas you find irritating.

How to Use Emollients With Sunscreen

Emollients keep your skin hydrated, and they are an important step in an eczema skin care routine—and so is sunscreen. How to use them together effectively? According to the National Eczema Society, you should apply your emollient a half hour before your sunscreen to avoid diluting the SPF on your skin.

This is particularly important if you’re using a physical sunscreen containing zinc or titanium oxide. Dr. Marcus says, “Physical sunscreens should always be the last step in a routine as they form a physical shield on top of the skin that shields the skin from UV radiation.” While a chemical sunscreen [that seeps into skin] will work if that’s your preference, Dr. Marcus insists, “For those with eczema, though, physical sunscreens tend to be a better choice as they’re better suited for sensitive skin and less likely to cause irritation.” Here are a few to try:

• CeraVe Hydrating Sunscreen Face Lotion SPF 50
• Vanicream Sunscreen Sport Broad Spectrum SPF 35
• Beautycounter Countersun Mineral Sunscreen Lotion SPF 30

Dr. DeRosa’s advice: “Try any new sunscreen on a small patch of skin to make sure that you can tolerate it.” Since people with eczema are sensitive, this can prevent a flare if a particular formula causes irritation for you.

Bottom Line

While sun exposure may help some patients manage their eczema symptoms, it comes with risks—including the potential to make your eczema symptoms flare up. For those who have tried first-line treatments with little progress, your doctor may recommend adding either phototherapy or sunlight therapy to your treatment regime, but both should be done with caution and with your caregiver’s advice.