I've been troubleshooting my acne for about 13 months now. I went paleo in March of 2010, started getting forehead bumps in June 2010, and then cystic acne around my mouth starting in August of 2010. It's been horrible-- up to dozens of cysts at a time sometimes. But I've done a ton of research, learned a lot about acne, and also experienced a ton of n = 1 self experimentation stuff. Only in the past few weeks have I found all (most?) of the answers I needed, so while I know that everyone responds to foods differently, I'll share the most pertinent of my experiences with you to see if it helps.

There are a lot of causes of acne. One apparently common one is face washing. I have found that all the redness that used to be "just a part of my face" is now completely gone that I don't wash with soap. Just water a few times per day, and, incredibly, I'm doing really well with that. Also, re: non-diet treatment: do NOT touch your face, do NOT pick your acne, no matter how horrific it looks. Trust me. Ack. It's not worth it.

Another prominent cause is an inflammatory diet. This just makes sense. If you're inflamed, your body is going to be sending all sort of inflammatory cytokines to sites needing repair, so you'll just keep getting more and more obviously inflamed. Up the omega 3s. I have gone up to eating a pound of salmon per day without ill effect (so far as I can tell-- I know that I probably exhibit some oxidative damage as a result).

Inflammation, so far as I can tell, is why food allergies can contribute to acne. If you're allergic/sensitive to foods, they can upregulate your immune response, and they can contribute to your general inflammation.

The final and, so it seems from my research and my own experience, largest cause of acne is hormone imbalance. Testosterone, particularly in females but also in males, if too prominent in the body relative to other hormones, will cause cystic type acne, mostly around the mouth but also on the cheeks and forehead. Our testosterone can get messed up for a number of reasons, but this is how various foods can affect our testosterone levels:

Dairy: I just read on a link from Seth Roberts blog (I know, helpful... sorry) that pregnant cows produce a protein that binds with another protein in our bodies which is responsible for binding with excesss testosterone and clearing it out of our systems... basically, it steals one of our testosterone "receptors" and this is how dairy makes such a big impact on people (other than gut issues and food sensitivities). This is HUGE for me. If I have just a sip of milk, a bite of cheese, I can immediately feel my face start burning, etc.

Soy: Soy acts as an estrogen in our bodies. If we continue to eat external estrogen, our bodies "forget" how to produce it themselves, and therefore including high amounts of soy in our diet will mess up our testosterone/estrogen balance. Best to leave it out altogether.

Industrial meat, chicken, eggs: Despite what the industry will tell you about "minimal" hormone levels in the animals, it's lies! all lies! Honest, though. I knew that testosterone was my problem from the get-go, since I have poly cystic ovarian syndrome, but I didn't understand why just about every paleo food made my acne worse until I found out that small amounts of hormones over large amounts of time can make a big difference. Eat local, grass fed, etc. I really do experience problems after just one meal of an industrial animal, and it was hugely frustrating to think it was the paleo diet or some macro nutrient ratio or something effecting me when it was in fact testosterone levels. I must confess, however, that I haven't tested grassfed beef. I have no idea if that would give me problems. There is a well-known correlation out there between high testosterone levels and high meat consumption, but that could be for a variety of confounding factors. It is possible that meat has an inherent testosterone increasing component that is outside of grass/grain fed cows. For right now, I'm avoiding all meat, just to be safe.

Oddly, pork in my experience seems to be better than both meat and chicken.

Sugars, high GI foods, etc: Insulin spikes and hyperinsulinemia both lead to increased testosterone production. For this reason, intermittent fasting has helped me, to a degree, mitigate my acne and other hormone problems.

Stress: increases testosterone.

Some more results of my self-experimentation and reading anecdotes:

It takes longer than two weeks to see the full effect of removing a food. I "removed" dairy a number of times to test my sensitivity, but only for a week or so. Because my acne was so bad, it decreased a little bit with removal, but not significantly for months. Loren Cordain recommends waiting 3 months to see real changes in your acne from food changes. Sometimes I get effects overnight, but in general, overall, my experience lines up with Cordain's recommendation.

Dairy includes butter. Don't let yourself just think it's lactose or casein effecting you. It could be an inherent part of the dairy itself, such as the proteins I described briefly above.

Rosacea is different from acne and should be treated more as an autoimmune condition.

If you're going to experiment with macronutrient ratios, give yourself a lot of time and try to set up the cleanest experiment. I've been wondering about whether or not I need more carbs in my diet for a year and kept thinking "maybe" after my experiments. However, it seems from this point (where all I have left is the scars of my acne) that macronutrient ratios aren't important (for me) at all.

Just to wrap it up with my experience:

I have Poly Cystic Ovarian Syndrome, which is a condition in the ovaries caused by male-hormone excess in a female body. I went paleo after my diagnosis but nothing really improved. I added dairy in huge quantities, plus meat and eggs into my diet (I had been a vegetarian). Slowly the acne came on, and then I became experimenting with eliminations with very little success. It took me a very, very long time to figure things out. It sounds obvious in hind sight, but the acne really could have been from anything. Or so I thought. In any case, I know a lot of women who started getting acne once going on a paleo diet, and I think this may be an (the?) answer. My acne got worse and worse over time, and as I eliminating the right foods, from dairy and then butter, then meat, then chicken, then soy, then eggs, it has very slowly abated. Now that I am on a diet that doesn't actively create new cysts and keeps my testosterone in check, the acne is going away, but, again, slowly. The lesson here is that it really can take a long time for our bodies to heal. I imagine that once I "reset" and get everything more in balance in a few months or so I will be able to eat these foods in smaller doses. I really just overdid it when I went paleo, sometimes eating 75 percent of my calories in a day from dairy.

Today, I eat vegetables (all vegetables, including nightshades, which I had feared for a long time for apparently no good reason), macadamia oil, coconut oil, avocadoes, and seafood. It's not much, but it's the "cleanest" diet I have found and, for me, it works. I know that this diet and these problems aren't quite the problem discussed in this thread, re: the rosacea, but it seems as though some commenters may be able to relate to my experience and others who read it.

My thoughts and opinions about acne are informed by my experience, as well as the vast volume of acne literature out there. There's not a lot, but if you dig around you can find SOME good stuff. There's a lot of appealing ideas out there that may in fact not have any merit, such as attributing acne to "unclean" proteins, improperly cooked foods, nightshades (the only anti-nightshade information I've ever found is anecdotal), lack of sleep.... it's important, I believe, to think about all of the things that cause acne on that particular spot of your face (it's true that different areas have different causes, though hormones play a role in all of them, and usually testosterone), and then think about how you might be affecting those causes in your life.

How sure are you that starchy tubers aggravate it? Adding them back in would likely correct all of the other side effects of low-carb that you're experiencing. It may be worth it to add back in a few sweet potatoes per day and give it a week to see how you feel. Even if what you're doing now cleared your skin perfectly (which it has not) it would obviously be at the expense of your overall health.

At the very least, you ought to supplement with vitamin C, since you're very likely deficient.

I've recently read all the acne questions and answers trying to find an all-encompassing universal theory of acne. Doesn't exist. One idea is that oxidized vegetable oils are the culprit. Not so if we are to take you at your word that you're not getting any in your diet. At least I don't see any evidence of this. Then dairy, fructose, intolerances of other allergens--all these get implicated. An elimination diet gets complicated when you eliminate (almost) everything, as you have described.

Recently I've had a flare-up of acne, and acne is not a problem I have had, at least not for a long time and not with this kind of severity. I think there are several classes of acne and they most likely have multiple, different causes. My acne is completely confined to the head and neck, which is odd to me. Could it be that this is not a dietary thing at all? I'm deeply skeptical, but at the moment I'm more inclined to implicate my razor than my diet. The zits follow an interesting pattern. They are all on the edge of where I shave.

I have not completely eliminated chicken, eggs, fish, and pork but I've much reduced my intake. (I've been clearing my fridge and freezer. Don't want to waste food.) But the most striking thing to me was the elimination of dairy. Striking in that I've read many accounts of how terrible it is for acne; yet a two week dairy elimination diet (strict) produced no reduction in my acne AT ALL. And it was not an easy thing to give up that heavy cream in my coffee, or the parmesan cheese, or the butter. All staples. I suppose it's possible that vegetable fats in my chicken (pastured, but supplemented with feed I'm sure), soy proteins in my eggs (WAPF says it ends up in the eggs and even the best pastured eggs get soy), or pork or fish allergens are causing this. My digestion is excellent so in my case I would conclude nothing, only note that there are too many confounding accounts. And dairy is not the cause (in my case, and it seems in yours, too).

Still, I will continue to eliminate the pork, chicken, eggs and the like, at least for now, as an experiment. And I'm buying an electric razor.

I did want to address the digestive issues. These should be addressed, perhaps with a GAPS/SCD/FODMAPS-type diet. If you can resolve the digestive issues and the acne is still a problem I'd be interested to know the outcome. For what it's worth, as a reformed IBS sufferer, fiber and probiotics were awful for me. Just awful. Getting rid of the lethal combo of plant matter and sugar for many months is what cured me. Now I can tolerate them increasingly. But it took about six months of an all meat diet before I got better.

Try an anti inflammatory.. like turmeric? I always wake up feeling less inflamed all around when I take it.

I'm having a similar problem with unexplained facial redness and flushing and am trying a low tyramine/histamine diet for a while to see if makes a difference. Did you ever figure out what was causing this?

You may not see this or may have already resolved your problem, but I thought I'd give it a shot. Are you familiar with Fructose Malabsorption? Researchers think that nearly a third of the population in the US is afflicted with it. That bloating and IBS-like stuff are signs you might have it. If so, all that coconut milk you've been drowning in could very well be your culprit. Coconut products can be a real problem for people with FM, due to their fructose content. If I were you, I'd leave off the coconut stuff (aside from coconut oil, which doesn't have fructose) for a few weeks and see what happens. You've tried just about everything else, right? Also interestingly, FM is associated with zinc deficiency, which causes acne, etc.

I follow gaps and i find out that cocunut and cocunut oil especially contributes to eczema or acne. It is not cleanse effect because just removed I have the clearest skin ever. I find a lot of people in paelo community as well. For some people it is healing because of good amount of fat but for others it is definetly not. The best source of fat should b meat not plant sources. I eat lot of raw dariy 2liters of kefir, red meat 1kg a day. 6 eggs 1kg veggies fish oil and primose oil.

I am struggling so much with diet and acne. One doctor i visited told me to remove all dietary lectins and it would clear my acne.

If these steps do not clear up the blemishes, try over acne medications counter. These products are applied directly to the skin.

 They may contain benzoyl [acne no more][1] peroxide, sulfur, resorcinol or salicylic acid.
 They function by destroying bacteria, and by drying the oil descamar upper layer of the skin.
 They may cause redness or skin peeling.

the red flushes you describe as well as the bumpy rash sounds like it might be demodex - a parasite on the skin that can look like acne. consider a parasite cleanse internally (humaworm ships to UK and is v good), then a liver flush - should also help with the digestive problems, etc. topically, apply diluted tea tree oil. good luck.

GAPS is the answer in my opinion.

I am documenting my journey with GAPS to fix Acne on my online blog. http://ashnand.blogspot.com/

I am 3 weeks in and already seeing progress.

As someone who suffered with acne throughout my teen years, I wish I would have known there was a real scientific connection between diet and acne then. Yes I had heard that greasy fried foods and chocolate caused acne but I found out those were myths so didn't think diet had any impact on acne. Once I started getting to the paleo diet I found out that a lot of the things I was going to be be cutting out could have actually been the cause or aggravater of my acne!

do you eat any seaweeds? have you looked into supplementing with iodine?