I Loved the Keto Diet — Until My Skin Fell Victim to This Uncommon Side Effect

Though I’ve always been mindful about eating empty carbs, I decided to take this commitment one step further and “go keto” back in April. If you’re unfamiliar with this trend, it basically means sticking to a high-fat, moderate-protein, extremely low-carb diet. I’d had some minor surgery that prevented me from working out for a month, and I figured eliminating all of those sneaky sugars in condiments, wine, and other foods I was accustomed to eating would help me maintain my weight until I could be active again.

[Editor’s note: As always, talk to your doctor before starting any new diet.]

All was going well — at least according to the ketone strips I was peeing on daily. These proved that I was effectively in ketosis, which means I was adhering to the diet’s rules and consistently burning fat. I was so happy with my results that even when I got the green light to go back to Pilates, I decided to stick with the diet.

However, around that time, something strange happened: I started waking up in the middle of the night with uncontrollable itchiness on my neck and chest. I tried hydrocortisone cream, cold compresses — you name it. The nocturnal itching (and significant loss of sleep) went on for about a week before it eventually subsided, leaving my skin with a strangely smooth and almost waxy texture that went away about five days after the itching finally stopped. Truth be told, I never associated this experience with going keto — until I did a deeper dive into the diet. Keep reading for a breakdown of this popular wellness trend (including how it works and what foods are recommended), how it can affect your skin, and what you can do about it. 

What is the keto diet?

According to Janelle Vega, MD, board-certified dermatologist in Coral Gables, Florida and co-founder of BIA Life, “The ketogenic diet is a low-carb, high-fat diet that is designed to get the body into a metabolic state of ketosis.” This state induces rapid weight loss — primarily of fat — in many individuals. “It eventually reduces blood levels of insulin and sugar, which has other health benefits, especially for patients with diabetes mellitus,” adds Dr. Vega. In addition, a ketogenic diet is said to have been used for those with epilepsy, cancer, polycystic ovary syndrome (PCOS), and diseases of the nervous system, such as Alzheimer’s and Parkinson’s. (However, if you have any of these conditions, it’s best to consult your physician before making any drastic dietary changes.)

How does the keto diet work?

“A ketogenic diet is designed to help your body use fat for fuel, reducing the need for blood sugar as an energy source,” explains Dr. Vega. In addition to burning fat (which is usually why we diet in the first place), studies have shown that the keto diet may also decrease appetite, which could increase your chances of weight loss. 

Other research has found that a ketogenic diet preserves lean muscle mass. This means weight loss is also more likely because muscles are known to help burn fat — consider the keto diet a double-whammy for fat burning. 

So just how low carb is the keto diet? Generally, limiting carbohydrate intake to 20 to 50 grams per day can stimulate ketosis. (For reference, there are about 60 grams of carbs in your average bagel.) “Depending on gender, weight, and level of physical activity, [reducing daily  carbohydrates to about] 50 grams may be necessary to prompt the body to use fat as a fuel source for weight loss,” explains nutritionist Nicolette Pace of nutrisource.org.

Plus, unlike other low-carb diets, like Atkins®, the keto diet takes things a step further by adding a specific ratio of macronutrients, which has been found to achieve and maintain ketosis. For optimal results, approximately five to 10 percent of your daily calories should come from your net carbs, with 30 to 35 percent from protein, and 55 to 60 percent from fat. “This can vary based on a person’s overall calorie intake,” Pace says. To put this in perspective, most Americans get 50 percent of their daily calories from carbohydrates, which equals roughly 250 grams if you eat 2,000 calories a day.

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So, what do you eat (or not eat) on the keto diet?

Clearly, carbs are mostly a no-go, but there is still plenty you can eat. “The keto diet should focus on fibrous vegetables such as celery, greens, cucumbers, and summer squash, as well as lean protein like fish, poultry, various meats, or soy,” explains Pace. “It’s also important to supplement the diet with fatty foods, including avocado, olives, MCT [medium-chain triglyceride] oil, coconut oil, and other oils.” Remember, you’re aiming to get up to 60 percent of your daily calories from fat, so don’t shy away from these good fats! 

Ultimately, success on the keto diet requires avoiding foods with a high glycemic load. “These are foods with a concentrated amount of carbohydrates in a small portion,” says Pace. These include dried fruit, candy, sweetened foods, yogurts, desserts, and (of course) starches in general. 

OK, but are there downsides? What about the keto rash?

The keto diet may be an effective way to shed unwanted fat, but it can come with a few unsavory side effects. Carbohydrate withdrawal can lead to a variety of symptoms that have come to be known as “keto flu.” These can include fatigue, dizziness, muscle soreness, headaches, and general irritability from all the latter. That said, if you experience these conditions three to four days after you’ve started the diet, you know your body is in ketosis and you’re effectively burning fat. 

[Editor’s note: If you experience any of the above side effects, be sure to discuss them with your doctor.]

Additionally, ketosis can cause bad breath, as acetone (a type of ketone, and the main ingredient in nail polish remover) exits the body, and is converted into isopropanol. The keto rash, however, is one of the more uncommon conditions associated with the ketogenic diet.

What are the signs of a keto rash?

The cause of the rash is not entirely understood, but skin experts do have some hypotheses. “An increase in ketones is thought to create inflammation of the blood vessels,” shares Dr. Vega. “This creates a rash in a lacy pattern, following the distribution of the blood vessels.” As if the itching and skin irritation weren’t enough, prurigo pigmentosa can lead to post-inflammatory hyperpigmentation, leaving behind a long-lasting, lacy brown pattern on the skin once the actual rash subsides. And, as with all hyperpigmentation, sun exposure can make matters worse. 

If you’re on the keto diet and begin to experience an extremely itchy, red rash in a lacey pattern on your torso, nape of the neck, or chest, you’re likely experiencing the keto rash. “As dermatologists, we are seeing a rise in this skin condition, which is officially known as prurigo pigmentosa,” explains Dr. Vega. 

How can you treat keto rash?

The easiest way to treat prurigo pigmentosa is to reintroduce carbohydrates to your diet. (Don’t blame the messenger!) This may help reduce inflammation on its own, but Dr. Vega notes that oral antibiotics are also often prescribed. It’s important to keep in mind that keto-induced prurigo pigmentosa is somewhat rare, but it is definitely possible that the low-carb, high-fat keto diet can lead to these skin symptoms. Even if the keto diet is not your weight-loss or weight-control method of choice, it’s best to see your dermatologist if you experience any unusual changes in your skin.

[Editor’s note: Be sure to talk to your doctor about any prescription products that may be used.]