Ruth Is Misdiagnosed With A Food Allergy, Turns Out It’s Keto Rash

[In perhaps one of the most pleasantly detailed e-mail exchanges I’ve had with a reader of this blog, Ruth shares her experience with the Keto Rash and how it was initially misdiagnosed as a food allergy when she saw a doctor.

The rash popped up for her after she began eating a low carb version of the Whole 30 program which is a diet I was also following at the time (If you’d like to know more about the Whole 30, I wrote a summary of the diet here).

The doctor gave her a corticosteroid injection followed by oral corticosteroids. Two days later the rash worsened. She immediately quit the Whole 30 and ate a bunch of carbs which improved the rash the next day.

While she was ‘treated’ with both carbs and corticosteroids, it seems more than likely that the carbs are what did the trick in her case, especially given the time course improvement and what we know of the rash.  I can’t thank her enough for all the photos she provided.

Here’s Ruth.]

Hi Philip!

Are you still featuring testimonials/personal stories on your keto rash site?

I cannot tell you how helpful your site has been in trying to figure out what happened to my own body… and I wanted to share my story! You’re more than welcome to share my experience on the site if you’d like, but just wanted to share in an email for now. Also happy to send pictures of what my skin looked like at the “peak” of my rash.

About 3 weeks ago, I started the Whole 30 program, not to lose weight but to just really reset my body and re-evaluate my relationship with food. As most people know, the gist of Whole 30 removes dairy, processed sugars, and gluten from a person’s diet for 30 days.

Unsurprisingly, the first day of Whole 30 was fine; I was consuming tons of protein (hard boiled eggs, chicken), nuts and fruit. I was eating very low carb, supplementing with potatoes here and there. However, about 2-3 days into the program, I started getting these incredibly itchy hive-like bumps and rashes. They first started at my ankles, which felt and looked like aggressive mosquito bites. I quickly brushed it off, as I thought it was something related to my minor eczema or the turn of spring (with so much pollen in the air?). However, the bumps started spreading across all parts of my body: it was worst on my shins and armpit areas, and it also spread to my lower back, neck and through to my scalp and ears, and I was soooo uncomfortable. At the peak of it, the bumps were slightly raised but flat, and the color was bright pink. To say the least, I was freaked out.

My condition got so bad across a 2-week span that I went to urgent care one weekend and ended up getting a cortisone shot and was then prescribed Prednisone, which you may know is just cortisone/steroid in oral form. The doctor said it was something I ingested and my body was having an allergic reaction, but I explained to him but that I never had a previous allergy to any of the foods that I ate. He thought it was due to my increased almond consumption but I wasn’t buying it – I’ve eaten BAGS of almonds in the past and although they have carbs, why would my skin suddenly react?

Two days after I started taking the medication and still on Whole 30, I decided to go for a run. It was a gorgeous warm afternoon and I thought it’d be good to get exercise. After about an hour, I get back home and the bumps were EVERYWHERE, most prevalent on my back and along my sports bra line and my pelvic region. I panicked, took a cold shower, popped more pills, then decided to scrap Whole 30.

After the work out incident, I turned up my carb instake (eating pizza, potatoes, crackers, cereal, white bread) like crazy. I don’t know if it was the medication or the reintroduction of carbs but I seriously think carbs did the trick. The bumps have gone done almost completely nearly a day after ingesting more starchy carbs. I still have to take my meds for another 10 days because I want to follow doc’s orders.

I have some hyper-pigmentation on my shins, where the keto rash hit the worst. Hopefully that’ll dissipate soon…

I had no idea keto rash existed until I googled “low carb itch” and found your posts. I’ve read nearly every story/study on your site, and it gave me tons of reassurance that keto rash can be treated with different options! It’s a bizarre condition but good to know I’m not alone. It sucks that my body wants to reject any low carb type of diet, but now I know it’s just better to simply eat the carbs (in good moderation, of course).



[I just loved Ruth’s in depth description of her experience and took her up on her offer to have her send some of the pictures she took during the rash at its worst.  I also asked if she thought about doing a higher carb version of the Whole 30 including things like sweet potatoes, white rice, fruits etc.]

Hi Philip,

Thank you for writing back! You’re more than welcome to share my story and use my name. At the very bottom of this email are some pictures.

Because the rash felt so severe, I simply felt the need to give up Whole 30 two weeks in, without trying to modify my carb intake. As you can imagine, I was too anxious and extremely embarrassed about my skin to try something different. I did attempt to eat more sweet potatoes and bananas for a day or two (and this is while I started taking the cortisone meds) and the rash still persisted; I’m willing to bet I just didn’t give it enough time.

I personally felt getting rid of the rash was way more important than keeping up with the diet. However, not all is a loss and I did learn a lot from those 2 weeks: like how much processed food I unconsciously relied on, and how lethargic my old diet made me feel.

What I found particularly interesting on your site was the study on The Keto Rash in 50 Koreans… I read the part where a few people had started a low-carb diet and was eating hard-boiled eggs and sweet potatoes (which is pretty much what I was eating on Whole 30!).  I am Korean-American so am wondering if this is prevalent issue in my race? Or maybe I’m not meant to eat so many sweet potatoes? Who knows. Totally speculative but would be curious to know if there’s a direct correlation between ketosis/keto rash and race.

Anyway, I gave up Whole 30 a week ago and am still on meds (will be done this week), but I am doing better about eating more sensibly and am including a little less dairy. Most importantly, I am happy to report I’m completely rash-free. 🙂

These pictures a bit out of order in terms of timeline but you can present any/all! At the peak of the rash, I did have huge traces of the rash all over my back, lower abdomen, and thighs – but wasn’t able to capture that.

keto 1: keto rash on my neck
keto 2: keto rash in armpit area
keto 3: keto rash back of my neck/upper back
keto 4: keto rash on my legs (this looks more like an allergic-reaction type of rash to me)
keto 5: keto rash on my left arm (this looks more like an allergic-reaction type of rash to me)
keto 6: keto rash on my neck [Shown above.]

Let me know if you have any more questions!

Thank you,


[I explained that I wasn’t entirely sure that this was something that mainly affected Asians especially since so many of the anecdotes I’m receiving are from non-Asians and many of the studies that are coming out now are in non-Asian subjects.  

 There does appear to be more information in the Asian medical literature regarding Prurigo Pigmentosa however I think it’s just because it was first discovered in Japan and they are probably more aware of it.

 I thought it’d be helpful if she could provide some follow-up pictures to document what her skin looks like AFTER the rash has disappeared, and she kindly obliged.]

Hi Philip,

Yep, see attached “after” pics. This is a week after giving up the diet and taking cortisone. As you can see, the rashes have totally cleared from my neck and arm areas and there are virtually no traces everywhere else, but there’s slight scarring on my shins. The itching was the worst on my shins so I scratched there the most; also, I spent quite some time in the sun over the weekend so the scarring/hyper-pigmentation on my leg looks more intense in the picture than it does in real life.

As for a new diet, not sure what I’ll pursue… my original intent with Whole 30 wasn’t necessarily weight loss but to try a body/system “reset”. I was tired all the time, especially through the work week so wanted to switch up the foods I ate.

Now, I’m just trying to do better about incorporating all the usual healthy stuff – more veggies/fruits and protein, less sugars and processed foods. For dairy, I love greek yogurt (which was prohibited during Whole 30) so am back to eating that but drinking less milk and eating less cheese. I love carbs but tended to abuse them regularly, so trying to moderate that – avoiding super LOW carb intake, of course!

Hopefully we’ll continue to find out more about keto rash/PP. The whole world needs to know!

I simply wanted to share my story so thanks for the opportunity to express my thoughts; hopefully my experience will provide a few people solace and reassurance.

All the best,


[I want to thank Ruth again for being so helpful with all of these photos and sharing her experience. I know everyone who visits this site will benefit from her generosity.]

Connect With Others

More posts are also trickling in on the Keto Rash Facebook Community, so feel free to chime in over there. If you don’t have a Facebook account, you can try posting in the Keto Rash Forums.

Support This Site

Keeping this site running takes quite a bit of time, so if you've found this site helpful, please consider making a small donation. Anything will help, even a cup of coffee!
(Visited 1,404 time, 1 visit today)


  1. Asli Umur

    I was diagnosed with seborrheic dermatitis and/or eczema more than once. My rash (when lo-carbing) is on my neck and scalp. It’s definitely caused by keto. It’s very good that you include different type of rashes as it might follow an unusaul pattern.

  2. dsharpe

    I have had this many times and it is caused by oxalic acid dumping when you go into ketosis. Cutting carbs will limit your oxalic acid content and your body begins to dump it.

    Check out this group there is lots of information about this here.

Comments are closed.