Fact-checked by Dr. Anthony Gustin, DC, MS.
Written by Brenda Godinez
- What the Keto Rash Is
- What Keto Rash Looks Like
- Why It Happens
- How to Alleviate Symptoms
- How to Prevent It
That itchy rash you’re experiencing is called “keto rash,” and it’s a normal side effect experienced by many (but not all) new keto dieters. It can definitely be annoying and somewhat embarrassing, but it’s not dangerous.
Rest assured that this rash is both preventable and treatable.
Keto rash is a rare inflammatory skin condition of unknown origin with a scary-sounding scientific name: prurigo pigmentosa. It can appear on people who are in the early stages of ketosis and was first reported in Japan in 1971[*].
The rash doesn’t have an exact cause, and it’s just beginning to be understood and researched in the West.
The rash manifests as itchy, raised skin lesions that can be red, brown, or light pink in color depending on the stage it’s in. Although it’s uncomfortable, it is not life-threatening or dangerous at all.
It looks similar to eczema and dermatitis, and typically shows up on the neck, back, chest, shoulders, torso, armpit areas, and — less commonly — face and extremities. Keto rash usually forms a symmetrical pattern on each side of the body in a net-like distribution.
Like most skin rashes, the keto rash can worsen if you exercise strenuously or expose the rash to heat, moisture, and friction.
Research shows the rash has four main stages[*]:
- Early lesions: The skin shows light pink raised skin lesions called “urticarial papuloplaques” that look like scratch marks. This stage can get overlooked or brushed off as a temporary rash.
- Fully developed lesions: This is the full-blown rash people get worried about. The skin shows more aggressive red skin lesions called papules, and sometimes papules include liquid-filled cysts (called papulovesicles) or, more rarely, pus-filled cysts (called papulopustules)[*].
- Resolving lesions: When the rash is receding, crusted, and scaly papules are observed. The lesions also start to get darker[*].
- Late lesions: As the peak of the rash comes to an end, the skin is left with a net-like pattern of dark spots larger than freckles, called “reticulated hyperpigmentation.” The pigmentation might remain long after the rash is healed[*].
And here’s the kicker: How long the rash lingers varies from person to person. It can last from a couple of weeks to several months. The two final stages (resolving and late lesions) tend to last the longest.
If you are experiencing the keto skin rash, here’s what you can expect:
Best-case scenario: It goes away after a couple of weeks.
Worst-case scenario: You’re one of the few people who get it every time your body enters ketosis.
However, there are several potential triggers related to the ketogenic diet that can make it appear:
- Ketone bodies. Acetone produced by your body during ketosis can cause perivascular inflammation (inflammation around your blood vessels) and trigger the rash[*].
- Excessive fasting. In one study, 50% of patients showed a relationship between fasting and keto rash[*]. When blood sugar levels are low during a fast, your body switches to ketosis and might cause the rash.
- Low-carb diet. A low-carb diet, especially one that causes you to lose weight very quickly, has also been related to the keto rash[*].
- Allergens. An allergic reaction is triggered in response to various keto-friendly foods.
- Nutrient deficiency. A nutrient deficiency from excluding some foods and not replacing them with nutrient-dense keto-friendly alternatives can manifest as a rash.
Causes of a Long or Recurring Keto Rash
Even with treatment, the keto rash might not go away completely after several months, or it might abate and reappear a few weeks later. This can happen mostly because of external triggers that activate your immune system and exacerbate your rash.
A study of 50 patients in Korea found that[*]:
- Five patients got the rash again after restarting their dietary modification (high-fat diet, ketosis, fasting, low-carb, etc). This means you might experience the rash if you get out of ketosis, then go back into ketosis.
- Five patients developed the rash once more after mechanical irritation such as bandage, body-scrubbing, or friction from clothing.
- Three patients regained it after sweating due to exercise or hot weather.
- Two patients developed it again after emotional stress.
Not knowing the exact cause of keto rash can make it hard to treat, but below are some of the ways you can find relief.
Full disclosure: The best cure for keto rash is debatable because the root cause is not clearly defined.
However, these five research-backed methods can help alleviate your symptoms:
1. Give It Time
The keto rash may go away on its own after a few weeks. If you’re new to the keto diet, it may just be a waiting game while your body adjusts. The longer you’re in ketosis, the more your body adapts to the production of ketone bodies.
Research finds that in patients who received no treatment, the lesions cleared spontaneously within weeks[*].
However, if the rash doesn’t go away on its own after a week or two, it’s time to try other options.
2. Eat More Carbohydrates
Some research suggests prolonged periods of fasting or being in ketosis correlate with the rash[*]. Out of the 16 patients in the study, eight manifested the rash after fasting for a long period of time, and six were in ketosis.
In a different study involving 50 patients, a dietary change (either ketosis, fasting, or a low-carb diet) was the suspected trigger for 17 people[*].
As mentioned above, ketones, excessive fasting, and a low-carb diet are the top three potential triggers of the rash, so this is the first factor that you should address.
To test if a ketogenic diet might be your trigger, do this:
- Try increasing carb intake just enough to get out of ketosis for a few days and see if the rash lets up.
- If it does, lower carb consumption and enter ketosis again.
- If the rash reappears, it can mean your body is sensitive to ketones.
In this case, consider a more liberal low-carb diet of around 50-100 grams of carbs per day, and combine it with intermittent fasting. This will still provide some weight loss benefits of ketosis and fasting.
Over time, you may be able to find your “sweet spot” with carb intake that provides benefit while reducing recurrence of the rash.
3. Try an Elimination Diet
Another potential trigger of the rash is an allergic reaction to a keto-friendly food. If you’ve recently introduced new foods or large amounts of certain foods, you want to test for food allergies.
- Dairy (e.g. cottage cheese, full-fat yogurt)
- Fish (e.g. tuna, salmon)
- Shellfish (e.g. oysters, clams, crab)
- Tree nuts (e.g. macadamia, almonds)
To find out if you’re allergic, try an elimination diet:
- Remove these foods from your diet for 30 days.
- Track if your rash has diminished or disappeared after this time.
- If your condition improves, reintroduce just one of these foods in your diet and wait one to two weeks.
- If the rash hasn’t reappeared or worsened, add a new food.
- Continue to add one new food every one to two weeks if no symptoms appear.
- If the rash resurfaces after introducing a new food, that’s your trigger.
4. Supplement With Micronutrients or Trace Elements
To rule out any nutrient deficiency-related causes, make sure to supplement your diet with vitamins and minerals that can be difficult to get when on a keto diet. Specifically, try supplementing with:
- Minerals: Sodium, potassium, magnesium, calcium. These minerals can diminish during a transition to a ketogenic diet and are vital for cell function and energy.
- Vitamins: Vitamin D, vitamin A, omega-3s from krill oil.. These vitamins are necessary for regulating inflammation. Since the keto rash is an inflammatory response, it’s important to get plenty of these nutrients into your diet.
- Bile Salts: Cholic, deoxycholic, chenodeoxycholic, and lithocholic acids, akabile salts, help your body break down fat into usable fatty acids.
Want a quick fix? Consider supplementing with Keto Greens Powder — it has all these vitamins and minerals and a lot more.
For more information about what supplements you should be taking while on the keto diet, check out this Keto Supplement Guide.
5. Talk to Your Doctor About Antibiotics
The antibiotics that have shown the best results are:
- Dapsone (minocycline has been preferred to dapsone because it has fewer side effects and results in a longer remission.)
Other medications that aren’t effective against the rash include antihistamines, topical anti-inflammatory steroids, and oral steroids.
Talk to your doctor about the potential risks and benefits of taking an antibiotic for your rash. You might consider following your antibiotic treatment up with a round of probiotics in order to help your body replenish your microbiome.
A word of caution: Despite antibiotics being extremely effective at getting rid of prurigo pigmentosa, they won’t prevent a relapse. A study in 50 patients found that[*] “although oral minocycline, with or without dapsone, was very effective in inhibiting the appearance of new lesions, these drugs did not prevent recurrence.”
This means they won’t fix the root issue of your rash, they’ll only make the current episode go away. That’s why you need to take additional measures to prevent a future relapse, like the ones outlined above and the lifestyle habits below.
Lifestyle Habits to Avoid a Flare-Up
Finding your internal triggers and avoiding them is an important first step. However, your rash can worsen or come back if you don’t pay attention to external triggers that exacerbate it.
As mentioned above, the main external factors that can make the rash return are sweating, friction, and emotional stress.
Adopt these simple habits to prevent a new rash:
Since sweat is a major rash trigger, try taking a few days off from the gym or at least reducing your workout intensity to minimize sweating.
If you do decide to exercise strenuously, be sure to shower immediately afterwards to wash off any perspiration (and the hitchhiking acetone irritants).
Rubbing can significantly aggravate the rash as well[*], so wear loose-fitting workout clothes to reduce the amount of friction on your skin.
Sweating from exercise can make you itchier, which makes you want to scratch (more friction), so it’s necessary to keep the sweating at a minimum.
Avoid Anything That Causes a Reaction on Your Skin
Since friction also flares up rashes, avoid:
- Wearing tight clothes, especially around the area where you have the rash
- Using any type of exfoliants on your skin, like homemade scrubs or a loofah
- Scrubbing too hard with your bath towel after a shower
- Using bandages
- Sleeping over the area that is affected, if possible
Keep the area moisturized with a cream or an oil that your skin can take. Lubrication will help prevent friction.
Try Stress-Reduction Techniques
Emotional stress can make your skin flare up, so adopt relaxing habits that support your mental health.
You can regulate your emotions through meditation, breathing techniques, taking walks, engaging in a relaxing activity (drawing, painting, reading a book), exercise, going to therapy, and talking about your problems with the right people.
Emotional stress has been linked to inflammation on the skin and can worsen existing skin disorders. This is because the dermal mast cells have a close connection with sensory nerve endings and may release signaling molecules that promote inflammation[*].
If you haven’t dealt with keto rash before and are worried about getting it, you’re probably wondering how you can prevent it.
Again, since the exact cause is unknown, there’s no clear solution for preventing the rash. However, now that you know possible triggers, here are a few things you can do:
- Transition into ketosis slowly. Don’t drop your carb consumption drastically or fast for long periods if you’ve never done it before. You want to lower your carb intake gradually until you are able to enter and stay in ketosis without signs of a rash.
- Pay attention to rash signs. Increase your carb intake as soon as you see signs of a keto rash to keep it from advancing to more developed stages.
- Supplement. Start supplementing right away to avoid deficiencies on your keto journey. Keto Greens Powder can provide you with vital micronutrients.
Follow these steps at least during the first few weeks you start on the keto diet.
Remember: The odds are on your side. It’s unlikely you will get a keto rash, as it tends to be rare.
But even if you do, there are simple ways you can actively treat and prevent it from happening again. Don’t let it scare you away from reaching your goals and getting all the benefits of the ketogenic diet.