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What’s the Keto rash and how to cure it?

Last updated: Oct 22, 2020 at 11:57AM | - Published on: May 16, 2019

Written by Raphael Sirtoli, MSc

Scientifically Reviewed by Sarah Neidler, PhD

When starting out keto, there are a lot of unpleasant side effects symptoms that you may experience as your body adjusts to a new style of eating. One of these is something called the keto rash. Before you start to worry, the keto rash isn’t a common side effect of going keto, but you should be aware that it can happen.

What is the keto rash?

infographic showing keto rash symptoms

The keto rash, also known as prurigo pigmentosa (PP), is a rare inflammatory skin condition[1] characterized by a symmetrically appearing red, itchy rash that develops around the trunk of the body and the neck. It is a type of recurrent dermatitis that can essentially develop in any individual, not just those following a ketogenic diet.

If you develop the keto rash, you need not worry. While it doesn’t look the nicest, the inflammatory stage, the rash, develops rapidly and generally does not last more than one week.

Why do we get it?

With respect to its development, there isn’t a lot of scientific evidence on the causes of prurigo pigmentosa. However, diagnostic criteria have been more clearly established.

Of the little research done on the keto rash, some researchers hypothesize an association between prurigo pigmentosa and conditions that commonly produce ketosis[2], including restrictive dieting, fasting, and highly elevated blood sugars. As popularity of the ketogenic diet increases, more cases of PP have been reported[3].

In a study looking at the signs and symptoms of 16 patients diagnosed with prurigo pigmentosa, a relationship between diet and the condition was found in 8 of the 16. Three other patients also experienced flare-ups intermittently as a result of dietary changes. This study concluded that excessive fasting leading to a state of ketosis can cause prurigo pigmentosa.

Similarly, a 2015 study published in the journal Pediatric Dermatology[4] found that prurigo pigmentosa is twice as common among girls and women than men, with 25 years old being the mean onset age. There was also a case report of a 17-year old boy that experienced an eruption of PP after adhering to a strict ketogenic diet.

Symptoms of the keto rash

The keto rash generally begins with small pink or red lesions that appear on the skin, but can eventually fuse into a larger, inflamed network of rashes. Usually, the keto rash appears with symmetrical distribution on the body. Most commonly it appears on the neck, central chest, upper back, lumbosacral area, and abdomen[5] and causes severe itchiness. However, unilateral and segmental distributions have also been reported.

Even though most cases of PP can be resolved, recurrence is not uncommon in the following months or years.

Most commonly, individuals experiencing and eruptions of the keto rash will go through four stages[6]:

#Stage 1 (early stage): Lesions present as small, raised pimple-like bumps that may resemble stretch marks. Often times, this stage is overlooked and brushed off as a simple rash.
#Stage 2 (fully developed): Lesions progress into darker red lesions and manifest as crusted papules. Sometimes these can include liquid-filled cysts or puss-filled cysts.
#Stage 3 (late stage): Lesions evolve into the smooth-surfaced, dark macula (pigmented area of the skin).
#Stage 4 (Resolving lesions): Lesions present as reticulated brownish macules only and often leave a net-like area of hyperpigmentation.

PP is differentiated from other skin lesions and conditions due to its unique reticular patterns[7], which can be present in any of the three stages mentioned above.

What causes the keto rash?

While the exact mechanism of development is largely unknown, growing bodies of evidence suggest there are some pretty likely connections.

infographic showing the causes of the keto rash

Gut dysbiosis

Some studies suggest that an altered gut microbiome may be a contributing factor to the onset of PP. Gut dysbiosis resulting from nutritional and other environmental factors may alter the profile of the gut microbiota and unfavorably modify the body’s immune response. Gut dysbiosis can lead to the production of bacterial toxins, increased intestinal permeability, and contribute to systemic inflammation engendering skin conditions like acne[8], rosacea, and eczema.

Dietary changes

Recent dietary changes may be linked to the onset of PP. In a study analyzing 50 cases of PP[9], 17 patients underwent dietary changes prior to the development of the rash. The dietary modification is not specified, but changes may relate to the transition into a low-carb diet.


In normal fasting, ketone bodies are produced and circulate in the blood in response to lower insulin and blood glucose levels. which causes the production of ketones for fuel. Ketonemia occurs when you have unusually high blood ketone levels. A 2015 study on PP[10], ketonemia and diabetes, found that ketones in the urine coincided with the onset of the PP eruption. As glucose and total ketone levels in blood decreased to within a normal range, the condition subsided. The blood ketones specifically had the greatest effect on the decrease of the eruption when compared with blood glucose. As such, it is likely that excess ketone bodies in the blood might be linked to the onset of prurigo pig­mentosa.

Another study[11] suggests that ketone bodies pass from blood circulation into tissues, enter cells, and reach the cytoplasm to be used directly in lipogenesis and to be oxidized by mitochondria. The surplus of ketone bodies may collect around blood vessels and lead to an inflammatory reaction, which may be a trigger in the onset of PP.

Mechanical irritation

Some research has indicated the friction caused by clothing can contribute to the onset and development of prurigo pigmentosa. A study[12] conducted by Kobayashi et al. (1996) showed that it can arise from contact allergic reactions to p-amino compounds that are used in the manufacturing of clothing.

Similarly, in a study[13] analyzing 50 cases of PP showed five patients developing PP after mechanical irritation from things like bandages, body-scrubbing or friction from clothing.

Extremely high blood sugar

While a less common cause of the keto rash, cases have been reported of patients development PP who have diabetes. This is likely due to uncontrolled blood glucose levels. As patients symptoms decreased when blood glucose levels were decreased and stabilized, this indicates that blood sugar control may have an active role in the development and progression of this condition.

How to treat the keto rash?

There are a few treatment options that can help control the development of prurigo pigmentosa. Complete resolution of the condition might take from one to several weeks[14]. However, lesions typically heal leaving behind a net-like pattern on the skin of hyperpigmentation[15] (darkened spots of skin) that may stay even after the rash has disappeared.

While treatment options may not work for everyone, some successful options include:

Let it run its course

In many cases of diagnosed PP, the lesions receded on their own. If it has developed as a side-effect of entering ketosis, allowing the body to adjust to using ketones as fuel may allow the rash to heal by itself.

Increase carbohydrate intake

Some research suggests that excessive fasting or being in a state of ketosis can initiate the onset of the keto rash. Based on current research, there is no successful cure for the keto rash that allows an individual to stay in ketosis. Increasing carbohydrate intake in order to decrease ketone blood levels has been proven effective at curing prurigo pigmentosa.

The most effective way to address this issue is to do a test. Increase your carb intake for a few days enough to take your body out of ketosis. By doing so, you reduce blood ketones and can see if the rash starts to heal. If it does begin to recede, lower carb intake again to get back into ketosis and note any changes to the rash. If the rash worsens, this is a sign your body may be reacting to ketones unusually.

A 2013 study on PP[16] and a strict ketogenic diet found that incorporating carbohydrates back into the diet helped to improve the severity of the rash. Similarly, if remaining on the ketogenic diet, careful prescription of carbohydrates[17] may enable to rash to heal without sacrificing ketogenesis.

Try eliminating allergenic foods

Inflammatory reactions can be caused by many foods, even keto-compliant ones. In order to determine if what you’re eating may be contributing to a rash flare up, trying an elimination diet may be worthwhile. Introducing new foods or eating large amounts of specific foods can cause the body to react in a way that it normally would not.

Here are some common allergenic foods you may want to try eliminating:

  • Eggs
  • Dairy
  • Tree nuts
  • Seafood

Try this protocol to do an elimination diet:

  1. Remove the specified foods from your diet for 30 days.
  2. Check if your rash has receded or disappeared after the period has finished.
  3. If it has, introduces one food again into your diet and wait 1-2 weeks.
  4. If the rash hasn’t come back, add one more new food and follow the same procedure.
  5. Continue adding in one new food every 1-2 weeks as long as no symptoms appear.
  6. If the rash appears at any point after introducing a food, that food is the likely trigger for the rash.

Fix nutrient deficiencies

While nutrients deficiencies are linked to a variety of conditions, vitamin A, vitamin B 12, and vitamin C, specifically, have been linked to a variety of acute and chronic skin conditions[18]. Vitamin D[19] and omega-3 fatty acids[20] also play a crucial role in the regulation of the inflammatory response. Since the keto rash is an inflammatory skin condition, there is some evidence to support optimizing levels of vitamin D and fatty acids may help to control or reduce inflammation levels.

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How to minimize the keto rash?

infographic explaining how to prevent the keto rash

Take NSAIDs or antibiotics

Medical doctors may prescribe prescription drugs, in the form of non-steroid anti-inflammatories (NSAIDs) or antibiotics, to help decrease the reaction associated with the keto rash. The three most common ones are minocycline, doxycycline, and dapsone. While they may help to reduce symptoms or completely heal the rash, they may end up causing more harm than good so weigh the risk-to-benefit ratio carefully.

As gut or intestinal dysbiosis have been linked to the onset of keto rash, it’s best to avoid medications that may further exacerbate that problem and have the potential to cause other problems in the future. Many studies[21] have shown that antibiotic usage leads to alteration of gut flora that can lead to a disruption in physiological equilibria and promote the long-term development of the disease[22].

Avoid wearing tight clothing that causes friction

As with any skin condition, tight clothing that rubs generally causes further irritation to already irritated skin. To avoid causing the rash to get worse, avoid wearing tight clothing or any garments that will rub on the area.

Also, avoid using skin exfoliants or bath accessories that will aggravate the skin more. And as difficult as it may be, try your best to avoid itching. We know that it’s hard, but itching may only make the problem worse.

Reduce Sweating

Sweating can be a major irritant to the skin, and it has also been linked to the onset and progression of prurigo pigmentosa[23]. If you can, avoid intense exercise or any activity that will cause sweating. If you must participate in an activity, avoid wearing tight clothes that will trap the sweat close to the skin and rub or scratch the body. Always shower and dry your body immediately after exercise has halted to avoid causing more irritation.

Preventing the keto rash

While there isn’t a lot you can do to predict the onset of the keto rash, there are a few measures that can be taken to limit the change of experiencing it.

infographic explaining how to prevent the keto rash

Go slow with keto

If you’re new to keto and your body has never been accustomed to using ketones for fuel, it may be wise to start slow to avoid the change of getting PP. Reducing carbs drastically may be a trigger for its onset, so it may be best to gradually decrease them until your body can adjust.

Add in supplements

As we mentioned, transient nutrient deficiencies can increase susceptibility to certain conditions or symptoms. With a targeted electrolyte supplementation regimen to ensure adequate intake of key minerals (especially during the adaptation phase of the ketogenic diet) you’re likely increasing your chances of limiting adverse reactions, such as the keto rash.

Reduce your stress levels

Emotional stress has been linked to a number of health conditions and has been shown to affect, and even exacerbate, a variety of skin disorders[24]. There have been increasing amounts of evidence that show emotional stress can influence disease processes and contribute to inflammation[25] via modulating the hypothalamic-pituitary-adrenal (HPA) axis.

Incorporating anti-stress techniques like meditation, deep breathing, or yoga may be beneficial in reducing stress levels. As well, activities like walking in nature, drawing, or reading can also promote relaxation.


The keto rash isn’t a common side effect of going keto, but it can happen. If you are one of the rare few who experience it, don’t worry. There are many ways to actively treat and prevent it from coming back, but don’t let it scare you away from ketosis. The benefits of going keto far outweigh some of the nasty side effects.

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Written by Raphael Sirtoli, MSc, Ph.D. (candidate)

Raphael Sirtoli has an MSc in Molecular Biology and is a Ph.D. candidate in Neuroscience at the Behavioral n’ Molecular Lab in Portugal. His understanding of metabolism, nutrition and clinical medicine is the base upon which Nutrita’s knowledge derives from. He loves open scientific debate, Crossfit, football, hiking, and cold water immersion.