Chili peppers are famously spicy, which is a draw for many people but a reason to avoid them if you have rosacea. In an NRS survey on spicy foods, 62% of respondents said hot peppers caused flare-ups. Capsaicin, the chemical in chili peppers that gives them their heat, is the culprit, but it’s unclear why it causes a stronger reaction in people with rosacea. Fortunately, new research out of the Chonnam National University Medical School in South Korea helps shed light on the mechanism by which capsaicin causes a flare-up.
In the small study published in the Annals of Dermatology, the researchers tested skin cells cultured from tissue samples taken from six patients with rosacea erythema (persistent redness) and six volunteers with normal skin by exposing the cells to capsaicin as well as capsazepine, a chemical compound that inhibits the response to capsaicin.
They found that the samples from rosacea skin showed significantly higher amounts of several neuroinflammatory molecules, including transient receptor potential vanilloid (TRPV) 1 and 4, cathelicidin LL-37, kallikrein-5 (KLK-5), tumor necrosis factor alpha (TNF-α) and vascular endothelial growth factor (VEGF), compared to normal skin. These substances have each been identified in past studies as playing a role in rosacea inflammation due to activation of the innate immune system. When exposed to capsaicin, the rosacea cells significantly increased production of TRPV1, LL-37, TNF-α and VEGF. The investigators then exposed the cells with this reaction to capsazepine, and found that the substance reduced levels of all four molecules by significant amounts.
The researchers recommended further research be conducted on the relationship between capsaicin and receptor activation, and suggested that capsazepine may be a potential therapeutic option for rosacea erythema.
If hot peppers or spicy foods cause your rosacea to flare up, it’s best to avoid them and look for alternatives. Bell and sweet peppers have the same crunch as their spicier counterparts, and opt for other spices that can add a lot of flavor to recipes without bringing the heat.
Kim HB, Na EY, Yun SJ, Lee JB. The effect of capsaicin on neuroinflammatory mediators of rosacea. Ann Dermatol 2022 Aug;34(4):261-269. doi: 10.5021/ad.21.223.
image courtesy of Marco Verch on flickr