Is keto rash a thing? Do you think you’ve had keto rash? It may be possible, though it’s very rare.
Let’s take a closer look at keto rash—what it is, why it happens, and what you can do about it.
What is keto rash?
Keto rash is a rare but recognized phenomenon—one that may become less rare as more people begin to follow keto diets. Formally called prurigo pigmentosa (PP), the rash most often occurs on the torso (chest and back) and neck, although it can appear on other parts of the body.
It’s characterized by slightly raised, red, inflamed, itchy patches or lesions and has been reported to occur within days to a few months of someone starting a ketogenic diet. (This type of rash can also be caused by other issues, but here we’re specifically looking at PP induced by keto.)
Based on the limited number of case reports in the medical literature, keto rash can affect anyone, but it appears to be more common among women and people of East Asian and Middle Eastern ethnicity.
What causes keto rash?
No one knows for certain what causes keto rash or why only a few individuals are affected. It appears to coincide with the state of ketosis, though, which suggests it may have a hormonal or metabolic trigger, or that the ketones, themselves, are the culprits. (PP has been reported in someone with ketoacidosis and has been observed in patients after bariatric surgery as well.)
It’s also possible that there’s a change in the chemical composition of sweat or other skin secretions when someone is in ketosis, and that this causes a reaction on the skin. (Out of curiosity, I once ran a urine ketone test strip through my sweat and it turned pink! So perhaps the acetoacetate in sweat is irritating to the skin—at least in the few people who experience keto rash.)
One paper offers up a more granular possible explanation: “…there has been shown to be an association between PP and metabolic or diet changes, most importantly the state of ketosis in the body. While this relationship is not totally understood, it is theorized that ketone bodies can induce neutrophil-mediated perivascular inflammation, a theory supported by the fact that PP responds well to medications that inhibit neutrophils, such as tetracyclines or dapsone.”
In plain English: the ketones may be prompting some sort of immune system response, with the rash as the result. (For most people, though, keto diets actually help improve a host of skin conditions, as opposed to causing them.)
Can you cure keto rash?
Doctors experienced in the ketogenic diet anecdotally report that keto rash usually fades on its own over time. Alternatively, it can be treated with antibiotics and this is the most common course of action. Most published reports of keto rash recommend that someone afflicted simply increase their carbohydrate intake, which will cause the rash to gradually disappear.
Owing to the popularity of keto diets, there may be some people who are following ultra-strict keto who don’t actually need to be limiting carbs to that extent. Many people can experience weight loss and improvements in health while following a low-carb diet but keeping carb intake just high enough to prevent ketosis, which seems to be the triggering factor behind the rash.
Those who experience keto rash but who require maintenance of a ketogenic state to prevent seizures or to support mental health can work with a professional to customize long-term treatment of the rash while following their therapeutic diet.
If you’re dealing with keto rash, something else to consider is whether you’ve introduced anything new into your diet that you weren’t eating before, but which you might be allergic to or sensitive to. If this is the case, eliminate those foods for a while and reintroduce them one by one so you can determine if one of them was the cause for the rash.
One article astutely points out that eggs, dairy, fish, and nuts and seeds are dietary staples for some people on keto, and these just so happen to be among the most common food allergens.
Bottom line
Keto diets can improve a long list of health issues, but it’s not always smooth sailing straight from the start. This very-low-carb way of eating can present some hiccups, but don’t let these small issues stand in the way of you following a way of eating that can radically change your life. If keto rash appears for you sometime after starting, look for a keto-savvy professional in your area who can help.
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