At some point during the last decade, while living in Washington D. C., I began to suffer from hand eczema. Painful red itchy inflamed dry skin covered most of my hands. It was usually triggered by cold dry weather in the fall and winter. It also flared up after a lot of cleaning — when my hands were exposed to a lot of water and soap, which dried them out. I was in my twenties when it began.
Eczema, also called atopic dermatitis, is believed to be a too-extreme allergic reaction. It is common. About 10% of American adults suffer from it, according to two recent surveys (here and here). In my case, a certain level of dryness is required. I believe the dryness, which may reduce a protective coating, allows something in the environment, like dust or pollen, to trigger an allergic inflammatory response.
The first thing I did to solve the problem was see a dermatologist, who prescribed a steroid-based cream. The cream did reduce the inflammation. It was just something to apply when the inflammation appeared. It didn’t stop it from happening. As I learned more about eczema, I decided this was an absurd solution. Steroids have nothing to do with the cause of eczema. At best they treated the symptoms, and had bad side effects (is anything creepier than “skin thinning”?).
Then a funny thing happened. A few years ago, my eczema disappeared. I didn’t notice it had stopped until this fall (2013), when it came back. I had forgotten about it. As soon as the weather turned cold and dry, it hit hard.
Why had it disappeared and returned? My environment had not changed in any big way. Nor, when I first thought about it, could I think of any dietary changes in the past year or two. Then I realized I had made a dietary change – and recently. In September (2013), I had stopped eating a few fermented foods that I had steadily eaten for the past few years — sauerkraut, kimchi, and kombucha. I had drank kombucha only a few times a month but had eaten sauerkraut or kimchi almost daily (3-4 forkfuls/day, $0.50/day). I had started eating them in 2011, hoping they would improve my health. The last time I had had eczema was the winter before I began regularly eating them.
Had the fermented food prevented eczema? This was not far-fetched. The ideas that (a) bacteria in food can influence your immune system and that (b) bacterial exposure can “calm down” an over-reactive immune system are both well-accepted. Review articles are here, here and here. There is lots of supporting evidence. An early example is the evidence behind the hygiene hypothesis – children in “dirty” places had fewer allergies than children in cleaner places. This article says “approximately 70% of the entire immune system” is in the gastrointestinal system.
Fermented vegetables like sauerkraut and kimchi are dominated by the bacterial species Lactobacillus plantarum. If sauerkraut and kimchi had prevented eczema, it was probably due to L. plantarum.
After multiple flares over a few months, I tested this idea. I found a probiotic supplement (Jarrow Formulas Ideal Bowel Support) solely composed of L. plantarum. Then I waited for my eczema to flare up again. When it did (early January 2014), I began taking the supplement (one pill daily, $0.50/day). Within three days, the eczema had completely disappeared. In the past, three days after it started the eczema got worse. It usually lasted about two weeks from start to disappearance. I had never seen it disappear like this. Usually at this point (3 days after it started) hand washing would be painful and make it worse. Now I could hand wash with abandon. Even more amazing: I could walk around outside during a cold spell without gloves, and did not have any exacerbation or return of symptoms. Being able to do these things three days into a flare up had never happened before.
I kept taking the supplement (one pill/day). In the past, before the fermented foods, I had at least some inflammation on my hands through the entire fall and winter, with extreme periods and less extreme periods. Now (February 2014) I have zero inflammation. In the past, dryness on my hands immediately led to inflammation. In normal people, dry hands are dry hands. I never have just dry hands. Dryness is a trigger. I’m not used to seeing a dry hand without inflammation on it. For the past few weeks, I’ve had mildly dry hands without inflammation. I’ve become a normal person with dry hands.
Several studies – which I didn’t know about when I saw that the probiotic supplement helped — support the idea that L. plantarum can reduce eczema. Two studies (here and here) found that L. plantarum inhibited house-dust-mite-induced eczema in mice. Another study found that L. plantarum inhibited allergic reaction and histamine-induced scratching (itching is a hallmark symptom of eczema) in mice. It concluded that L. plantarum “may improve allergic diseases, such as . . . atopic dermatitis”. In another mouse study, L. plantarum was successfully used to reduce dust mite allergy. The most impressive evidence was from a 2012 study done with children in South Korea. All of them had eczema. Those given L. plantarum improved much more over 14 weeks than those given a placebo.
In contrast to my success, many studies have found no effect of probiotic supplements on eczema. One review concluded “Initial meta-analyses suggest no benefit of probiotics [supplements] in the treatment of eczema or asthma.” Maybe they tested the wrong bacteria or used a too-small dose. I haven’t noticed any effect of yogurt (which contains different bacteria) on my eczema.
After I posted about this in my blog, several people tried something similar and reported what happened. Overall I would summarize their results as modest improvement. The most positive result was this: “After 5 days of radish kimchi the eczema in that person [a family member] is very clearly receding and, in a few spots, is completely gone. From prior experience, it would not have done this on its own.” The least positive result was no change, which a few people noticed.
My interpretation is that kimchi and sauerkraut – that’s what everyone tried — have far less L. plantarum than the probiotic supplement I took. This article considered sauerkraut “probiotic” when the concentration of L. plantarum was “higher than 10^6 colony-forming units (CFU) per gram of product”.
This sauerkraut maker says their sauerkraut has 8 x 10^6 CFU per gram. A serving of sauerkraut might be 60 g, so the total number of L. plantarum in one serving will be roughly 5 x 10^8. In contrast, the probiotic supplement I took supposedly contained 10^10 CFU – a factor of one hundred more. A daily dose of 5 x 10^8 CFU might eliminate eczema if you eat it for months, as I did, but might produce much more modest results after just a week.