I regularly receive slightly panicked messages from people saying they started keto and within the first two weeks they developed an unsightly rash, often with itching. It is very common indeed, although it does not happen to everyone, and it is quite understandable people get into a panic over it. So lets talk about keto rash.
The medical term
Keto rash is a rare inflammatory skin disease of unknown origin but some medical experts refer to it as the known skin condition prurigo pigmentosa, although it has not been officially determined it is in fact the same condition. There seems to be a correlation though between ketone production and the development of prurigo pigmentosa hence the belief the two are the same.
Generally speaking one can assume all keto rashes are also prurigo pigmentosa, but not all instances of prurigo pigmentosa are associated with ketosis.
What are the symptoms of keto rash?
Keto rash usually shows up as itchy, raised skin lesions that can be red, brown or light pink in color depending on the stage the rash is in. Although it is not nice to look at and can definitely feel uncomfortable, it is not dangerous in any way. It can resemble eczema and dermatitis and it usually shows on your neck, back, chest, shoulders, torso, and armpit areas. Sometimes it occurs in the face, but this is not as common.
Keto rash can have different stages in terms of how it looks, from slightly raised pinkish skin marks to vividly red lesions that may or may not be filled with fluid. Healing keto rash can look scaly or even more like brown freckles. Another noteworthy fact: it is usually symmetrical on each side of the body.
Like most rashes, the keto rash worsens if exposed to heat, sweat, friction, and other potential skin irritants.
How long does it last?
There is no set time frame for how long your keto rash will last. For some people, the rash will last only for a couple of weeks to a month, while others will struggle with it for several months to non-stop. In fairness, the latter is really quite rare, in fact, most people I have spoken to about keto rash were clear of the rash in just weeks, not months, let alone years.
What causes keto rash?
Although many studies have found a link between prurigo pigmentosa and ketosis, the exact cause of the rash is unknown.
However, here is a promising theory behind the cause of keto rash: a ketone body called acetone. Here are the facts:
- most of the subjects in research studies done on the subject of prurigo pigmentosa had lifestyles/diets/conditions that promoted ketone production;
- people who are on a keto diet and get the rash usually start to experience itching soon after they get into a state of ketosis and the itching stops within a day or so if they up their carb count and exit ketosis;
- insulin production was found to speed up the healing process of prurigo pigmentosa in one study;
- the rash often gets worse in warmer weather and after exercise due to increased sweating;
- the usual distribution of the rash is typically in the areas where we tend to sweat the most;
- when first entering ketosis, we produce more acetone than usual. Acetone is useless to the body, so it is excreted out with the breath and through sweat;
- when acetone is released through sweat in high concentrations, it can irritate the skin and cause dermatitis-like symptoms.
In short: as a result of producing more ketones for fuel due to your state of ketosis you create more acetone. This acetone most likely will be excreted with your sweat, which in turn exposes your skin to excess acetone and causes an inflammatory reaction, itchiness, and lesions on the skin that results in what we call keto rash.
Possible keto rash triggers
- perivascular inflammation i.e. inflammation around your blood vessels can happen during ketosis and trigger the rash;
- there may be a relationship between fasting and keto rash: stress due to lower blood sugar levels plus a deepened state of ketosis during fasting may be possible triggers;
- being new to a low-carb diet, especially one that causes rapid weight-loss and ketone production, has generally been associated with the occurrence of keto rash;
- an allergic reaction can be triggered in response to various keto-friendly foods previously eaten in smaller quantities or not at all;
- a nutrients deficiency from excluding certain foods, can lead to a rash. For example, vitamin A, niacin, and omega-3 deficiency can all provoke rash-like symptoms if not paid attention to;
- chlorinated pool water, acetone and other potential skin irritants are all associated with prurigo pigmentosa.
Ways to deal with keto rash
Let it heal on its own
Really the simplest way to deal with this: wait it out, it may very well disappear by itself in a few weeks time. I know it did for me and for many others as well. Treat it as part of your body adjusting to the state of ketosis and adapting to using fat for fuel. If you find this does not work, or if you are too uncomfortable, regard the other options below.
Up your carb count
While this is certainly NOT the option I would suggest you go for immediately, some of you may find the rash just stays around for too long for you to handle and so you may need to increase your insulin levels to help the rash heal (as discussed earlier).
To test if ketone production actually might be the cause of your keto rash, you can:
- try increasing carb intake just enough to fall out of ketosis for a few days and see if the rash starts healing;
- if it does heal, lower carb again and get back into ketosis;
- if the rash then reappears it means you are probably sensitive to ketones and may need to follow a low carb diet that doesn’t provoke consistent ketone production.
To keep your body from going into ketosis you may need to consume 50-100 net carbs daily. This is still considered a low-carb diet! You will eventually be able to find your sweet spot regarding carb intake that helps you improve your overall health while actively reducing the recurrence of the rash.
Any dietary change always increases the risk of triggering food allergies. Simply by introducing new foods to your diet or suddenly eating large amounts of certain foods (hello avocado!), we can trigger a reaction that may be responsible for your keto rash.
The most common keto-friendly foods that trigger allergies are:
- tree nuts
- peanuts (technically not a nut but a legume and as such for strict ketonians NOT part of a keto diet)
To find out which food is the culprit you will need to eliminate suspect foods from your diet:
- remove one of these food groups from your diet every 3-4 weeks;
- check if your rash starts to diminish or disappear;
- if so, then you found a food that is triggering your rash;
- if not, then introduce the food back into your diet and eliminate a new food from the list every 3-4 weeks;
- You may have multiple food triggers, so make sure you try eliminating and reintroducing each one to see how your body reacts.
Supplementation of vitamins, minerals, and other nutrients
To rule out any deficiency related causes, you need to make sure to supplement your diet with vitamins and minerals that you may not be getting enough of. However, I always advise to only do this if a blood panel in fact shows you are deficient in any.
Generally speaking I do always advise to supplement sodium (Himalaya salt on food), potassium (never in pill form but by adding small amounts of LoSalt to your water) and magnesium (you can use a pill form, a dermal spray or take a (foot)bath with Epsom salts). These minerals are typically excreted in higher quantities while you are transitioning to a ketogenic diet hence the need to supplement. Make sure you are getting enough of each one because they are vital for multiple metabolic functions.
Getting enough Omega-3s helps in reducing inflammation and improve skin health. Also make sure you are drinking enough water. Most people lose a lot of fluid when they first start keto, which can actually increase the concentration of acetone in the sweat and in turn provoke keto rash. Drinking more water may help dilute the acetone so that it doesn’t accumulate on your skin when your sweat. Do not overdo it though: there really also is such a thing as drinking too much water.
Make sure you eat anti-inflammatory foods
Without an inflammatory response, keto rash would not occur. The itchiness and lesions that characterise the rash are a result of our immune system being activated by what is happening in and around the skin cells.
To help lessen this inflammatory response and reduce the severity of your rash, consider adding these foods to your keto diet:
- glycine, an amino acid, has a variety of protective effects against inflammatory diseases like keto rash. To get more glycine in your diet you should eat more animal skin, collagen, bone broth and/or supplementing with glycine directly;
- wild fatty fish contains a lot of healthy omega-3s so try to eat sardines, salmon and other fatty fish on a regular basis;
- here is one to try: turmeric is a potent anti-inflammatory so try taking it as a supplement for example a curcumin/bioperine supplement;
- virgin olive oil contains high levels of oleocanthal — a phenolic compound that possesses anti-inflammatory properties which help reduce acute and chronic inflammation.
Avoid skin irritants
Skin irritants, like chlorinated pool water or chemicals in laundry detergent or even chemicals found in clothes themselves may trigger the rash or cause them to flare up. So try to avoid:
- any chemicals or products that irritate your skin
- scratching of your skin
- wearing tight clothes, especially around the area where you have the rash
- scrubbing too hard with a towel
- use of bandages.
- sleeping on the affected area
Avoid excess sweating
Because acetone in sweat is a major rash trigger, it is best to keep yourself from sweating or at least avoid prolonged exposure to sweat.
Take a few days off from the gym or reduce your workout intensity so you can minimise sweating. If you do sweat, be sure to shower directly after to wash off any perspiration but do also avoid using too hot water.
Relax and de-stress
Emotional stress has been linked to inflammation on your skin, and can worsen skin disorders including keto rash. If you want to improve your skin health in general but eliminate keto rash specifically, you are best of incorporating activities into your life that help relieve stress.
Try meditation, breathing techniques, taking walks, doing yoga, engaging in a relaxing activity (drawing, painting, reading a book, listening to music), low-intensity exercise, going to therapy, and spending quality time with people you love.
If all else fails: discuss it with your doctor
All methods described above to help eliminate keto rash are gentle and perfectly fine to try without medical advice. But if they do not work you may find discussing it with your doctor to be more helpful or even necessary. Your doctor can prescribe certain antibiotics for example. Antibiotics can treat the rash in some cases but keep in mind they do not prevent recurrence of the rash. For that reason antibiotics should only be used as a last resort after trying all other options.
Please take note: certain medications have been proven to be ineffective for keto rash. These include: antihistamines, topical steroids and oral steroids.
Can you prevent keto rash?
So suppose you want to start your keto lifestyle today and you are seriously freaked out by all this talk about keto rash: you just want to know if it can be prevented, right? To be blunt, because the exact cause is unknown there is no clear prevention plan. But here are three things you can do:
- While as a coach I always suggest you lower carbs to below 30 gr net carbs immediately from day 1, if you are really worried about keto rash you will want to lower your carb intake gradually until you can enter and stay in ketosis without any signs of a rash. It may make it a bit tougher for you in terms of withdrawal symptoms from your high carb diet, but perhaps your skins will be helped by it;
- Increase your carb intake as soon as you see signs of a keto rash to keep it from progressing to more advanced stages. Do not wait till it gets worse, stay on top of it. You can also try using other strategies from the list of potential cures above to help it heal.
- Immediately start supplementing to avoid deficiencies.
Keep in mind though: it is NOT a given you will get keto rash, in fact, the odds are on your side and you will most likely not have to deal with it at all.