Great Keto Rash question from a reader… Wish I knew the answer

Hi Philip,

I just discovered your site and think it’s great to have a source that tries to bind all the information and research on this ‘keto mystery’ together for the advancement of knowledge and treatment.

I have started a keto diet three times now in a period of about 2 years, the most recent one a week ago. Furthermore, I also experience the keto rash. The first time it happened was after about 1-1,5 months in. I had the rash for max. two weeks and then I went on vacation and basically the diet got botched. The second and third time though the onset of the rash was much faster, both times around 3 days in ketogenesis. So far this is similar to what I read in the stories of others.

What I noted however that is perhaps interesting and that I haven’t read anywhere is that all three times my rash both started in the exact same location and the spreading followed the exact same pattern. This indicates that, at least in my case, the rash is not completely random. Rather, there seem to be certain (small) parts of my body that are always affected and parts that are never affected. I’m not sure if this was mentioned anywhere before or if this is common knowledge but I have not read about this detail before. Maybe you know more information on this?

Regardless, the fact that the initial starting point and spreading is exactly the same three times in a row seem to suggest to me that this is more than a coincidence. Now, I have seen enough pictures of keto rash to conclude that everyone’s keto rash is in different places and of different magnitudes. However, the fixed spreading pattern within individuals could still be a potentially valuable insight in to the cause of keto rash.

My question to you is two-fold: 1) To your knowledge, do you know if my observation can be corroborated by experiences from you or others that you know of, and 2) if it is, could this fixed spreading pattern be an indication to certain causes of keto rash/rule out certain causes of keto rash?


Here is my response… which of course is unsatisfying because I’m responding with more questions.

Unfortunately I don’t have answers for you regarding either question.

It is something I’ve wondered though. What makes the skin on my chest and upper back different than the skin on my belly, legs and arms? If ketosis is a systemic phenomena, why is the skin rash in selective locations?

Differences in skin flora?

I don’t think an answer exists at this point… But I agree with you in that I think there’s something there.

Anyone else have ideas?

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  1. Kita

    The rash just started on me a little over a week ago. The main difficulty with it is just how much it affects my sleep (it’s 3:45am when I’m writing this). This is because when it showed up overnight it showed up in all the spots where I have the most pressure placed during my sleep – that is, under my left arm where my arm and side of my chest touch, and far more down my right side, which is in contact with the mattress (I usually sleep on my right side). Additionally since having it I’ve started sleeping on my back more to move away from those sensitive spots – and sure enough after that it started appearing on my shoulders and the centre of my back – again, the spots which would lie heaviest on my mattress as I slept.

    This makes me the placing is to do with sweating, particularly sweating that is somehow blocked off due to contact or pressure. The fact that it mainly appears pretty uniformly on backs/shoulders, as well as anecdotally people reporting of it coming up in patterns matching the backs of their office chairs, seem to maybe confirm this suspicion.

    1. (Post author)

      Yeah, I’m sure sweat glands likely have something to do with it. It’s also been shown that sweat glands are where certain microorganisms like to live, so there may be a relationship there…

  2. Matt

    Hi Philip,

    I have recently started back on Keto, and was actually looking at your site for another reason when I noticed your Keta Rash info.

    I had a scenario identical to yours, I was Keto for about a year previously – no rash. This time I got a rash, which I went to see the DR about. The Dr diagnosed me with Pityriasis due to the trunk being the only affected area.

    Having read through the site, I am being drawn toward gut flora as being a good angle to try – it would also explain why antibiotics work.

    So, since I’m determined to stay ketotic, from tonight I’m going to start taking some good quality probiotics to see if that helps. If not, I’ll see if I can get some antibiotics.

    Either way, I’ll let you know how I get on.

    1. (Post author)

      Thanks! Please keep us posted!

      1. paleoinc

        I take probiotics everyday and it doesn’t help.

  3. Celeste

    I have rashes in my forearms… it gets reddish and then itchy everytime i eat foods with grains and sugar. It sometimes becomes my indicator if the food has some hidden grains mixed to it. If i eat sugary sweet foods, it starts with the forearm, next my back, last would be my scalp. Since i could not see my back anf scalp, i could not visually describe it but i could feel the bumps..
    For a year i fell off the keto wagon and was living a carbfull life. The first month of eating high carb diet it was really itchy, but after awhile as my body got accustomed to a highcarb diet it eventually faded. It came right back again when i started doing keto again at the same right spot. I have applied anti-fungal cream on it and it vanished. Only to come back again when i “cheat”… i like to call it my anti-cheat!

  4. Debbie

    I also have recently had an experience similar to what Rob described, where I got my first bad keto rash after a bit over a month of ketosis, then within a week I healed myself after finding this blog (thanks!) by just eating carbs, I took supplements but I don’t think any made a difference (probiotics, spirulina, green tea). This week, about a month later, I dieted again and after three days, which means I just went into ketosis, the rash started to appear again. I ate carbs immediately (5 fiber crackers) and it settled back down. I think after having the rash one time my body is now hyper sensitized to ketosis and even just a little bit will cause the rash, like how an allergy to food works. I’m bummed about it because it means I can’t really do this diet which works for me. My rash also appears in the same place. I didn’t even question why because that’s how these things are, certain rashes show up in certain places, others in other places. I recognized this as the keto rash specifically because of where it appeared (neck, chest, abdomen, upper back) which was how it was described here and in that Korean study.

  5. Rossellina

    I think one of the best things to do is give the child a bath with banikg soda, and let them soak in it for a while (if they like the bath). But if you really want to use diaper cream the website below has a really good article on it.

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