Eczema is a chronic dermatological disorder. It is a targeted issue that causes redness, lesions, and itching. Many rumors circulate about the effect of the sun on eczema. What do scientific studies say about this? Can the sun help alleviate eczema?
Eczema, in a nutshell.
Theeczema is a chronic inflammatory disease of the skin that primarily affects infants, children, and adolescents, but can also appear in adults. It manifests as red, rough, and extremely itchy skin lesions, which can affect different parts of the body. Eczema is a common dermatosis and is the second most widespread skin disease, after acne.
Individuals suffering fromatopic eczema secrete large amounts ofimmunoglobulin E (IgE) in response to environmental allergens. Eczema is also caused by a dysfunction of the skin barrier, due to a lack of sebum, lipids, and cell adhesion molecule production. As a result, the skin barrier can no longer perform its protective role and allows allergens to pass through more easily. Eczema can also be acquired and independent of genetics. This is referred to ascontact eczema, triggered by a specific allergen.
Can the sun alleviate eczema?
Individuals with eczema do not all respond the same way to sunlight. While some notice an improvement in their skin condition with the arrival of warmer weather, others see their lesions worsen. This is referred to as photosensitive eczema. This is a photo-allergy, meaning it's a cross-reaction between a product containing an allergenic molecule and the UV rays of the sun. It's quite rare, but it does occur.
The use of phototherapy is sometimes suggested for individuals suffering from eczema. This method employs UV rays to alleviate the red lesions and characteristic itching of this skin condition. Numerous studies demonstrate its positive effect on eczema. One study, in particular, showed that regular exposure of 29 children to UVB with a restricted range of wavelengths (300-320 nm) for 12 weeks resulted in a 61% decrease in their SASSAD (Six Area Six Sign Atopic Dermatitis) score. This score is often used to measure the severity of eczema.
Another point in favor of the sun: it stimulates the synthesis of vitamin D . A recent study showed that vitamin D increases the production of cathelicidins. These are molecules that act against Staphylococcus aureus, bacteria that sometimes colonize eczema-prone skin. Staphylococcus can cause secondary infections of eczema, sometimes with significant consequences. Vitamin D has a protective effect against this. Moreover, it promotes the production of proteins necessary for the functioning of the skin barrier, which limits dryness and the entry of pathogens.
Eczema and Sun: Is it Really a Good Idea?
Despite the various elements mentioned above, it is quite difficult to determine the effect of the sun on eczema. Indeed, phototherapy is different from direct sun exposure. When one exposes oneself to the sun, it is without medical supervision. Moreover, natural UV rays have a much broader wavelength range than that used in phototherapy. As for vitamin D, sun exposure is not the only way to obtain it for the body. It is possible to take it orally via dietary supplements.
Finally, even though the sun provides certain benefits, it's important to remember that it can also prove to be harmful to the skin and cause skin problems other than eczema (sun spots, melanomas, premature skin sagging...). To avoid these, it's crucial to apply a broad-spectrum sun care product, meaning it protects against both UVA and UVB rays, before each exposure, even if you have eczema. Opt for a cream with a rich texture, which can nourish your skin in addition to protecting it from the sun.
TAYLOR A. & al. Narrowband ultraviolet B phototherapy in children with moderate-to-severe eczema: a comparative cohort study. The British Journal of Dermatology (2014).
PALMER D. Vitamin D and the Development of Atopic Eczema. Journal of Clinical Medicine (2015).