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MDs Reveal a Surprising Side Effect of the Keto Diet + Easy Ways to Sidestep It

About 45% of American women are dieting on any given day, and the low-carb keto plan is one of the most popular around. And while it’s helped people lose a lot of weight, women who have tried the diet are experiencing an unexpected side effect: keto rash. We talked to doctors and diet experts to find out what causes the rash, how to treat it and how to avoid it. Read on for the details.

What is the keto diet?

“At the heart of the keto diet, you limit your intake of carbohydrates to the point where you trigger ketosis — a state where your body burns fat instead of sugar for fuel,” notes cardiologist Bret Scher, MD. In a nutshell, the plan advises aiming to ensure 70% of your daily calories come from fat.

Osteopathic physician Anna Cabeca, DO, who lost 85 pounds on a keto diet she created, recommends eating plenty of healthy fats like olive oil, coconut oil, avocado and nuts. You’ll get 25% of your daily calories from protein, a task easily accomplished by including about 4 oz. of grass-fed beef, free-range chicken or turkey, eggs or fish in each meal. Then, you’ll get 5% of your daily calories from carbs. (Click through for more easy keto tips and learn how it helps women over age 50 lose weight.)

Why the plan is so popular? Because it works. Research shows a keto diet helps people shed four pounds more per year than those on a low-fat regimen. Though such results are impressive, there are potential pitfalls, cautions future dermatology resident Hannah Kopelman, DO, host of the popular podcast Derm Club, which focuses on treating dermatological conditions with top experts in the field. (Click through to learn how a keto diet can cause urine that smells like popcorn.)

“There can be side effects of the diet, including ‘keto rash,’ clinically known as prurigo pigmentosa, an inflammatory skin condition characterized by an itchy, red-to-brown, net-like pattern, typically on the torso, chest or back,” she says. It’s about twice as common in women as men, likely because we’re simply more inclined to be keto-diet devotees, says Dr. Kopelman. Just read on to discover the culprits behind this rash and easy steps you can take to soothe it.

Related: Yes, the Keto Diet Can Affect Your Periods — Here’s What to Expect

What causes keto rash?

While the jury (that is, science) is still out on exactly what triggers it, Dr. Kopelman reveals that there is a strong link between the rash and ketosis, a state in which your body gets energy from fats, not carbs. “It seems to be an inflammatory reaction to ketones, chemicals the body produces during fat metabolism.” The good news? Keto rash is relatively rare. Still, peace of mind is priceless, especially when it comes to the health of your biggest organ: your skin.

If you’ve recently developed irritating mystery spots on your upper body, your best bet is to visit a dermatologist because the rash could be caused by anything from allergens in the environment to your laundry detergent, notes Dr. Kopelman. In the meantime, she advises being your own best detective by pinpointing a few telltale signs of keto rash:

  • Papules or vesicles (raised or bumpy patches)
  • Crusty or scaly skin
  • Severe itchiness
  • Hyperpigmented red or brown spots

Related: What Is That Rash Under Your Breast? What the Experts Say & How To Get Rid of It

What to do about keto rash

Keto rash does tend to spontaneously disappear after just a few weeks, assures Dr. Kopleman, but there are easy strategies you can use to help soothe your skin and speed recovery:

1. Share your diet with your doctor

It sounds simple, but the power of communication is perhaps your first, best defense. “The thing that struck me during my research is that the rash is often underdiagnosed or clinically missed,” she says, explaining that doctors tend to confuse it for eczema or contact dermatitis caused by irritating skin products. “If you go to a dermatologist, they’ll likely ask about the kinds of foods you’re eating, but a primary care doctor may not pick up on diet as a potential cause for your rash.”

If you are diagnosed with keto rash, your doctor may prescribe an oral antibiotic like minocycline or doxycycline, says dermatologist and immunologist Delphine J. Lee, MD, PhD, Chief of Dermatology and Residency Program Director at Harbor-UCLA Medical Center. “These medications, which we also use for the treatment of acne, are thought to act on the immune system, curbing its ability to cause inflammation — and the itchiness of the rash is due to that very inflammation,” she says. Indeed, a study in The Journal of Clinical and Aesthetic Dermatology showed that people treated with 100 to 200 mg of oral doxycycline daily saw their rash resolve after an average of 18 days.

2. Baby your skin

As with anything from run-of-mill winter-induced flakiness to itchy eczema, a moisturizer goes a long way to soothing keto rash and improving your skin barrier — the body’s defense against irritants including chemicals and allergens, notes Dr. Kopelman. “I love Vanicream products because they’re super gentle and free of dyes and fragrances that may irritate sensitive skin.” (Buy on Amazon, $5.09 for 2 oz.) Dr. Lee notes that you might also want to swap out perfumed soap for a gentler option, like unscented Dove. A word of caution: “If you have sensitive skin, try a new moisturizer or soap on a small area of your skin first, like inside your arm, just to make sure it doesn’t irritate you.”

What’s more, when skin is inflamed due to keto rash, there can be a slight, temporary increase in pigmentation, a process called post-inflammatory hyperpigmentation, explains Dr. Lee. The deceptively simple solution? Sunscreen. “If you’re exposed to the sun’s ultraviolet light without protection and you also have this post-inflammatory response, you’re getting a ‘double hit’ of pigmentation that can leave brown or reddish spots.” To shield your skin, she recommends applying SPF 30 or higher, even over the winter months. Not to worry, the pigmentation will eventually fade, she promises, adding that the timeline depends on factors like your genetics and skin sensitivity.

3. Reintroduce *good* carbs

Just when you feared adopting a keto diet meant never again seeing your morning bagel beckon to you from across the breakfast table, there’s hope for your inner bread lover: “Gradually reintroducing a moderate amount of carbohydrates into your diet helps the ketones that spur inflammation to exit your bloodstream,” says Dr. Kopelman. In fact, a study in the Hawai’i Journal of Medicine & Public Health revealed that people who added carbs back into their diet saw their rash symptoms improve dramatically.

And choosing the right carbs means you won’t undo all the gains (or in this case, losses!) you’ve made by following the keto regimen, adds gastroenterologist Will Bulsiewicz, MD, author of Fiber Fueled. “There are a number of foods you can eat and still maintain the keto diet,” he confirms. “Greens and cruciferous vegetables like broccoli and cauliflower, for example, are high in fiber, low in sugar and provide a good source of healthy carbohydrates.” 

4. Consider taking these supplements

“Omega-3 fatty acids help support skin health and dial down inflammation,” notes Dr. Kopelman. Aim for about 250 to 500 milligrams of EPA and DHA daily. One option: NOW Foods, Ultra Omega-3, 500 EPA/250 DHA (Buy on Amazon, $22.94 for 180 softgels).

Another supplement to consider: ox bile digestive enzymes. “They facilitate gallbladder health to help it digest fat better,” explains functional medicine practitioner Lauryn Lax, author of Eating Healthy Is Killing You. That’s important because breaking down fat more efficiently curbs the inflammation thought to cause keto rash. Lax advises taking one capsule of ox bile enzymes with a meal daily. One option: Herbage Farmstead, Ox Bile Supplement, 500 mg (Buy on Amazon, $12.99 for 60 capsules).


For more on the keto diet, keep reading:

This Keto Detox Soup Makes It Easy to Lose Weight Fast — Without Feeling Hungry

“I Lost 224 Lbs — More Than Half My Size! — With This Keto Hack That Cured My Cravings”

This content is not a substitute for professional medical advice or diagnosis. Always consult your physician before pursuing any treatment plan.

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