If you just started the keto diet and developed an itchy rash, don't panic. What you're experiencing is a rare and harmless side effect of the ketogenic diet. The keto rash is not a sign that you're doing something wrong or that the keto diet is in any way harmful. It's simply an unusual reaction to entering ketosis.
The keto rash is not really limited to the ketogenic diet. It happens to people on vegetarian and vegan diets as well. Scientists have also documented the rash in people with diabetes. Learn more about the keto rash in the lines below. We explain what it is, why it happens, and how to treat it.
In medicine, the keto rash is called prurigo pigmentosa which is defined as "a rare inflammatory skin condition of unknown cause ." This definition, although disappointing, it's the best we got. Scientists know very little about the keto rash and why it happens. It's also extremely rare, so researchers have little opportunity to study it.
What we do know is that the keto rash is red, itchy, and recurrent. It also seems to happen more frequently in people with increased ketone levels like those with diabetes or those on a keto diet. Luckily, the rash is easy to treat, and most people recover quickly without any long-term problems.
The symptoms of a keto rash include:
- Inflamed, itchy, and raised spots forming a network-like pattern
- The spots occur on the back, abdomen, and chest and are symmetrical.
- The rash tends to go away and recur
- The rash gradually worsens forming cystic lesions
- As it begins to resolve, the keto rash becomes scaly
- The rash leaves dark spots (hyperpigmentation) once it goes away
If you believe that you have the keto rash, you're in the unlucky few. The keto rash is extremely rare. Most cases (around 200 of them) are documented in Japan and only around 50 cases are documented outside of Japan since it was first discovered in 1971 . Researchers don't know why the Japanese are more susceptible to the condition, but genetics factors are likely involved.
Why the Keto Rash Happens
As already explained, no one really knows why the keto rash happens. Researchers did notice that the it occurs more frequently in people who recently switched diets [3,4]. This was especially true when the diet in question boosts ketone levels.
Since elevated ketones are a common trigger for the keto rash, we can't help but wonder why ketones and even changes in the diet would cause such a reaction? Some possible explanation for this include the following:
- Ketones released through sweat irritate the skin– The rash affects areas where we tend to sweat a lot. Since some studies show that ketones can also exist through sweat , it is possible that the acidic quality of ketones irritates the skin.
- A drastic change in diet triggers an allergic reaction– The ketogenic diet excludes foods you commonly eat and demands and greater intake of foods you eat sparingly – this can unveil a previously-unknown food allergy.
- Nutrient deficiencies – Dietary changes can also lead to nutrient deficiencies when the diet is not well balanced. The skin is sensitive to nutrient deficiencies and many deficiencies will show first on the skin .
- Toxins irritating the skin – Fat tissue serves as storage space for environmental toxins that the liver can't eliminate . When you lose weight quickly through a keto diet, all those accumulated toxins are released into the bloodstream and into the skin.
Other possible explanations include a weakened immune system, sweating, hot weather, and stress. However, the basic culprit remains a low-carb or ketogenic diet and the elevated ketones that go with it.
How to Treat the Keto Rash
Doctors usually prescribe antibiotics to treat the keto rash. One study even shows that taking broad-spectrum antibiotics daily can cure the keto rash within one week . But keep in mind that antibiotics are most suitable for people with a severe rash and they can come with their own set of side effects.
If you're experiencing only a mild case of keto rash, we suggest treating it the natural way first. Chances are you only need to tweak your diet a bit to get rid of the rash.
Consider doing the following:
- Discontinue the keto diet– Mild cases of the keto rash resolve quickly when you increase your carb and fluid intake. You don't have to quit the diet forever, though. Once the keto rash resolves, try dieting again and see if the rash recurs.
- Eliminate food allergens – dairy, peanuts, eggs, and seafood are common food allergens. Try eliminating one each week and see if the keto rash subsides. Alternatively, you can always ask your doctor to check for food allergies to know for sure.
- Minimize sweating – It is quite possible that ketones in your sweat are causing the rash. If possible, avoid going out in hot weather and skip doing any workout until your rash resolves. A good idea is also to wear cotton clothing to absorb the sweat.
- Keep stress at bay – Stress weakens your immune system making it next to impossible to fight infections. Don't stress while on a keto diet, get enough sleep, and keep stress at bay by sticking to a daily schedule.
- Take supplements – Zinc, B vitamins, and vitamin C are important for skin health and the immune system. Deficiencies of all are common so taking them in supplement for can help control the keto rash. Another popular supplement that seems to work well for many dieters is fish oil.
The last option is to give it time. Many keto dieters just let the rash resolve on its own with great success. Make sure to call your doctor if the rash doesn't go away, though. Suffering for more than a week is not a good thing and you always want to rule out other conditions.
The keto rash is unpredictable and has no known cause. So, preventing it is a bit tricky. Luckily, you probably don't have any reason to worry about the rash since it doesn't affect most people. However, if you already experienced the keto rash and want to prevent future recurrences on a keto diet, consider the following:
- Start slowly– Don't go head first into ketogenic eating. Instead, reduce your carb intake gradually week by week so your body slowly adjusts to rising ketone levels.
- Include plenty of nutritious foods – By eating foods high in vitamin C, E, and zinc, you'll keep your immune system strong and functioning and, hopefully, the keto rash at bay.
- Eat enough omega-3 fatty acids – Research shows that the food we eat is deficient in omega-3 fatty acids . Omega-3s are essential for a range of functions in your body, one of which is regulating the immune system.
- Make sure you're healthy – Starting the ketogenic diet after a cold or during a stressful period in your life isn't the wisest thing to do. Your immune system needs to be strong and functioning to prevent side effects while your body is adapting to keto.
Preventing the keto rash is difficult, especially if you already had it once. However, most people who do develop the rash have one or two episodes during their keto journey. Be patient and try a range of natural approaches to prevent the keto rash.
If you're 100% sure that you have the keto rash and that it's the result of switching to a keto diet, you don't have any reason to worry. The rash is not dangerous, and research hasn't linked it to any harmful outcomes. The condition is limited to the skin that's irritated due to rising ketones.
The rash isn't an indicator that something is intrinsically wrong with the keto diet or that you're ill. Remember, the ketogenic diet is a scientifically-confirmed and medically-approved method of treating a wide range of conditions. It's also safe for most people when well-planned.
However, if you have type II or type I diabetes, you may want to be careful. The keto rash could indicate that your ketone levels are too high, and you could be at risk of ketoacidosis. Ketoacidosis is a life-threatening condition where ketones in the blood rise to abnormally high levels and this changes the acidity of the blood. Test your ketone levels daily to stay safe.
If the keto rash is making you second-guess the keto diet, keep in mind that this rare and harmless condition also happens on vegetarian diets, fasting, and to people with diabetes. The rash also likely has little to do with the keto diet and more with your body's unusual reaction to elevated ketones.
If you happen to get the keto rash, you can easily treat it with antibiotics if you're afflicted with a severe case. Alternatively, you can always try and boost your immune system by reducing stress, taking multivitamin supplements, and sleeping more.
The keto diet drastically changes the way your body uses food for energy. These changes can lead to a range of side effects, including the keto rash. However, all keto side effects are temporary. Once they subside in a couple of weeks' time, you'll only experience the benefits which make so many dieters return to keto eating again and again.
With all that being said, don't let the keto rash discourage you from reaching your keto goals. Use our tips to treat and prevent the rash and give keto a try.