How To Treat and Prevent It

The keto diet, a high-fat, low-carb plan, isn’t without side effects. Some side effects include bad breath, diarrhea, flu-like symptoms, and a skin problem known as keto rash.

Keto rash, also called prurigo pigmentosa, is a red, itchy body rash with bumps that can look like a web. Here’s more about the rash, including the main symptoms and most effective treatments.

Keto rash is a rare form of dermatitis or skin inflammation. It appears as raised, red, itchy bumps on the skin that take on a web-like appearance. Keto rash can appear anywhere on the body, but it’s more common on the chest, back, and neck.

The rash may resemble contact dermatitis or an allergic reaction. However, keto rash can be distinguished by the brownish discoloration of the skin that remains after the inflammation subsides.

Keto rash can last from a few weeks to a month. It also varies in how quickly it appears after someone starts the keto diet. Some people may have the rash after six days, while others may not see the rash until four months later.

The exact cause of keto rash is unknown. However, there are some theories about why it happens.

One theory is related to the types of food you typically eat on the keto diet. “Because the keto diet is 75% to 90% fat, people may be eating large quantities of common allergens, including dairy, eggs, and seafood,” Cynthia Sass, RD, Health contributing nutrition editor, told Health. Rashes are one of the possible reactions to these and other allergens.

Another possible cause, according to Sass, is that the diet’s lack of fiber and plant-based foods alters gut bacteria in a way that increases the production of inflammatory compounds. “A high intake of red meat, another common pattern in a keto diet, can do the same,” added Sass.

Still, other than ketosis—a state when the body burns fat instead of carbs—triggers for prurigo pigmentosa can include:

Diagnosis will entail a healthcare provider asking about your medical history, including your symptoms. The provider may also want to know about any factors that could make you susceptible to having keto rash, like any dietary changes with carbs.

In many cases, keto rash can be eased by adding carbs back into your diet. Tetracyclines are antibiotic medicines also used to treat prurigo pigmentosa. These medicines supposedly keep the skin rash from forming.

Preventing keto rash requires getting your body out of ketosis. If your body remains in ketosis, prurigo pigmentosa can happen again.

If your keto rash doesn’t go away by making changes to your diet, speak with a healthcare provider. A provider can also help you get to the bottom of what caused the rash in the first place and made it noticeable when you started keto.

You should also see a healthcare provider for a rash if:

• It’s all over your body, painful, or infected
• The rash happens suddenly and speeds quickly
• You have a fever
• You start having blisters

Keto rash, which consists of skin inflammation and red bumps, is a potential but rare side effect of the keto diet. The cause of the rash is unknown, and how long it lasts and when it shows up varies.

Keto rash is treatable and preventable. However, see a healthcare provider if your rash doesn’t go away or comes with symptoms like fever or a rash with blisters.