Does Sun Exposure Help Eczema?

Symptoms of atopic dermatitis (eczema) often improve with exposure to sunlight. However, for some people, sun exposure may worsen—or in rare cases even trigger—the skin condition.

Whether you're in the former or latter group, you should always take measures to protect your skin from the sun. This includes limiting your time outdoors during certain hours of the day and using sunscreen with an SPF of 30 or higher.

Benefits of Sun for Eczema

Some people find that sunlight improves their symptoms of atopic dermatitis (eczema), a chronic skin condition that causes redness, dryness, and itching. The exact reason is unknown, but it's likely a combination of increased production of vitamin D and decreased inflammation.

Vitamin D

Sun exposure increases the production of vitamin D in the body. By doing so, it may indirectly modulate immune function in the outermost layer of the skin (epidermis).

People with eczema often have low concentrations of cathelicidins—compounds that are correlated to a lower risk of bacterial, viral, and fungal colonization—in their skin. When vitamin D increases, the immune system ups the production of cathelicidins, which may indirectly improve eczema symptoms.

Inflammation

Exposure to UV radiation from the sun may reduce skin inflammation, alleviating some of the dryness, itching, and rash that characterize eczema.

A study published in the Journal of Allergy and Clinical Immunology found that when skin is exposed to UV light (like the sun), it triggers the release of nitric oxide into the bloodstream. That chemical activates T-cells which decrease inflammation. Because eczema is caused in part by an exaggerated immune response, this may help reduce symptoms.

Prevention

Sunlight exposure may play an important role in the prevention of skin conditions like eczema. One study found that infants who received less UV light—regardless of whether or not they were taking a vitamin D supplement—were significantly more likely to have eczema than babies who had moderate sun exposure.

Negative Effects

For some people with eczema, sun exposure causes more harm than good. This may be because of one of the following factors:

• Skin damage: Long periods of sun exposure cause sunburn, which increases symptoms of dryness and itchiness.
• Photoaggravated eczema: Some people find their existing symptoms worsen with exposure to UV rays. If you get flare-ups only in areas that were exposed to the sun, your eczema may be photoaggravated.
• Photosensitive eczema: In rare cases, eczema is caused by exposure to UV rays. People with this form of the condition need to avoid sun exposure.

Risks

Generally speaking, natural sunlight is considered safe for people with eczema when exposure is limited to 10 to 30 minutes several times per week. However, heat and sweat are common eczema triggers, so anyone with the skin condition should avoid sun exposure during hot weather.

Safety Tips

Even if sun exposure improves your eczema symptoms, too much of it can damage your skin, causing signs of aging and increasing your risk of skin cancer.

If your healthcare provider recommends sun exposure for your eczema, here's how to do it safely:

• Limit your time: Start with five minutes and see how your skin reacts. If there is no redness, tightness, or tingling, you can gradually increase the exposure time over days or weeks.
• Choose early morning or late afternoon: Avoid sun exposure during 11 a.m. and 3 p.m. when the sun is strongest.
• Use protection: UVA radiation is associated with skin aging and UVB causes sunburns. Using a sunscreen with an SPF rating of 30 or higher allows for sun exposure while limiting damage to your skin. Look for an emollient-rich sunscreen that is alcohol- and fragrance-free.
• Never indoor tan: Tanning beds and booths utilize high doses of UVA radiation that increase the risk of eczema exacerbations, as well as skin cancer and premature aging.

Phototherapy

Phototherapy (also called ultraviolet light treatment) exposes skin to controlled bursts of UVB or UVA rays. It is usually done in a healthcare provider's office and utilizes a special device that is approved by the U.S. Food and Drug Administration.

Phototherapy is typically recommended when the first-line treatments for eczema (such as topical steroids) fail to provide relief. Research suggests this treatment may be more effective than sunlight exposure in the treatment of moderate to severe atopic dermatitis.

Summary

Sun exposure is one of many treatment options for eczema. Some people find it helps decrease their symptoms of the condition.

But even though it's natural, that doesn't mean sun exposure is completely safe. Be sure to take protective measures—such as using sunscreen—to prevent skin damage. Speak with your healthcare provider before trying this or any other therapy option.