There's a Scientific Reason Your Hair Hurts When You Don’t Wash It

Ever notice how your hair hurts when you haven’t washed it in a few days? It’s not just you—greasy hair pain is a thing, according to dermatologists, and there’s a legit scientific reason for it.



Listen, we've all gone a few too many days between shampoos. Even with the miracle that is dry shampoo, scheduling regular full washes can sometimes fall to the bottom of the to-do list. Gross? Sure. True? Definitely. (Hey, washing and styling is time consuming.) Of course, when you don’t have time to wash your hair, you can end up with a scalp full of grease. And unfortunately, that’s not all you can get from skipping washings.

If you don’t wash your hair for awhile, oils that your scalp produces naturally accumulate around your hair shaft, promoting the overgrowth of yeast on your scalp, explains Joshua Zeichner, M.D., a New York City-based board-certified dermatologist and director of cosmetic and clinical research in dermatology at Mount Sinai Medical Center. This can lead to skin inflammation which causes redness, itchiness, and scaliness. “In some patients, inflammation may manifest most with an ache,” he says. Translation: Your hair hurts.

Before you freak out and run to the shower, getting what sounds like a yeast infection on your head doesn’t mean you’re a dirty person (even if you are a little lax on the hair-washing front). That yeast that grows on your scalp is malassezia yeast, which lives on everyone’s bodies, Zeichner explains. When levels of the yeast rise, like when you don’t wash your hair for a few days, your body is more likely to react, causing the itchiness or discomfort, says Cynthia Bailey, M.D., a diplomat of the American Board of Dermatology and president and CEO of Advanced Skin Care and Dermatology Inc.,

There can be other factors at play with greasy scalp pain, too—namely the fact that you also tend to put your hair up when it’s oily, and that can also feel uncomfortable, Bailey says.

Luckily, there's help—maybe not shockingly, it involves washing your hair.

If you’re having scalp pain due to greasiness, you want to try to reduce yeast levels with an antifungal drugstore shampoo, like Nizoral 1 percent shampoo, Zeichner says, adding that a tar extract-based shampoo like Neutrogena T-Gel, can continue to reduce inflammation. “Remember that while these shampoos may wash hair, they should really be used as scalp treatments,” he says. That means you should apply them only to your scalp, let them sit there, and lather for the length of time that it takes to sing the alphabet. Then, wash them off and clean your hair with your regular shampoo.

That should help clear up any scalp pain, but if it persists, it’s time to see your dermatologist—it could be a sign of another scalp condition.