Though we all know Hailey Bieber for her “glazed donut” skin, even the most dewy and clear-complexioned among us will suffer from some kind of skin issue. Celebrities—and billion dollar-acquired beauty business moguls—get spots, rashes, and irritated skin too.

Dr. Mary L. Stevenson, MD at NYU Langone Health, previously defined perioral dermatitis for Vogue as “a skin condition which results in dry, flaky red skin as well as red bumps or papules. It can look like acne although it is a distinct diagnosis with some overlap in treatment. In addition it can be itchy, red, dry, and swollen.” What that looks like in reality: every couple of months, you can experience irritated, uncomfortable rashes on a concentrated area of your face (usually, the mouth) that are next to impossible to cover up, and, takes a long time to clear up. Perioral dermatitis is most common among women between the ages 25 to 49, and can last for weeks or months.

Bieber took to her Instagram Story to share her recent experience of a perioral dermatitis flare up, posting a makeup-free selfie to show the small bumps and texture on the lower half of her face. She captioned her Story saying that it “always flares when I’m traveling a lot, sleep deprived, hormones, the wrong SPF, new products, stress.” Derms can’t be totally sure yet what causes DP—the research isn’t there yet—but plenty of DP sufferers will say similar. (This writer included—anything from a new product gifted to me at Christmas that has some fragrance or actives I’ve been unacquainted with, to a few summer holidays, or a particularly stressful stretch of work can stir the bumpy skin).