Eczema and Sun: Good or Bad Idea?

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.