MilkAllergy, thanks for sharing your experience! I know that this was posted many years ago, but if you happen to see this, would you mind giving an update on how your dermatitis is doing? Are you still able to keep it under control through diet, and have you figured out anything more about what foods trigger the condition? I would also be very interested in hearing from any other Internet People who have similar success stories to share.
Now I'll explain my own situation a little bit. This is probably going to end up being long-winded, but I always find it valuable to read the stories of people who are battling with (or who have purportedly conquered) SD. Reading their experiences is like a fun-but-sometimes-frustrating exercise of piecing together a really complicated puzzle. If anything, I've learned that (1) the Science behind these sorts of skin problems is severely lagging and pretty much all we have to help us are personal anecdotes, and (2) everyone's condition is unique and we're all trying to figure out what works for us. But, by providing a detailed and honest account of my journey to-date, hopefully I can provide some helpful puzzle pieces to someone who is going through the struggle. And even if nobody reads this, writing it all down will at least be cathartic!
I'm a 27-year-old male and have suffered with SD for many years. Actually, I'm not sure whether I should call it SD or eczema or something else entirely (different dermatologists have told me different terms), but from what I've read SD seems to fit the bill. The dandruff I don't mind so much, but it is the dry, red, flaky skin around the mouth that I struggle to cope with. When it flares up badly it makes me not want to go outside, and it always sucks when it hurts to smile or laugh. I've dealt with dandruff since I was a kid, but the mouth rash appeared when I was a teenager (shortly after I started shaving with a dirty razor - not sure if that was related).
I was always able to keep the dry flakiness under control by using an aftershave lotion everyday, but at one point in college I made the mistake of trying to improve my condition by using an assortment of oils, lotions and other skincare products. As my skin became drier, redder and nastier I thought that oiling it up even more was the answer. It was at this point that my condition got to be the worst it has ever been - large flakes of peeling skin coming out of the woodwork in gross-looking patches around my mouth - yuck. I felt miserable and my self-esteem sunk to an all-time low. After I came to my senses I was able to get things back under control (but not cured) after I decided to drop all of the oils and only apply (sparingly) the original aftershave lotion that I had been using since I was a teenager.
At around this time I saw a dermatologist and he prescribed me a hydrocortisone cream and anti-fungal shampoo. The redness seemed to only get worse, so I cut the experiment short after a few weeks and discontinued both. So much for that.
After doing some of my own research I found out that antibiotics are commonly prescribed to treat "perioral dermatitis", so I tried a course of doxycyline, and WOW. The red, dry flakiness got knocked the **** out after only a few days. I felt very happy and believed that I had finally cured myself. I think I was taking 100 mg twice daily for about 8 weeks. But during this time things were definitely not completely peachy. While I was taking the antibiotics, and for months afterwards, I suffered from increased anxiety and had multiple incidences of panic attacks. In retrospect I strongly suspect that it was the antibiotics that caused these symptoms. For this reason, and because of all the stuff we've all read about how antibiotics negatively affect your gut bacteria, I would only recommend this route as a last resort.
In any case, the dreaded red and flaky skin came back with a vengeance about a year and a half later. Again, it appeared after I grew a beard and then shaved it off with a razor that hadn't been washed in a long while, so I have a strong suspicion that shaving with a dirty/unhygienic razor is _somehow_ a trigger (and I have read at least one corroborating anecdote on the internet. What a weird mystery this disease is).
I decided not to repeat my experience with antibiotics and made a second trip to the dermatologist's office. This one said "a-ha, eczema!" (just like the last one said "a-ha, seborrheic dermatitis!") and told me to rub Aquanil HC on my face (a mild, non-prescription steroid lotion). I was skeptical since the steroid lotion that my previous dermatologist gave me seemed to do nothing except make things worse, but I gave it a try. And, viola!, the flakiness disappeared. There was still noticeable redness and dryness, but at least I did not have to deal with unsightly flakes of skin peeling from my face whenever I opened my mouth to laugh or eat a burger, so I counted it as a major victory.
After reading about some of the undesirable side effects that can come from long-term use of topical steroids, I decided to research other treatment possibilities. It was at this point (just a couple months ago) that I started to seriously consider that diet, particularly food sensitivities, might play a major role in my SD. I read about FODMAPs (a fledgling area of research that is backed by a lot of science, I should point out) and realized that I suffered from many of the symptoms that a low-FODMAP diet tends to address: bloating, bowel movement issues, halitosis. I gave it a shot and, quite dramatically, those three issues disappeared for me, which my whole life I had just assumed were normal (my stomach no longer protruded by 3x its original size after a meal, I no longer had miserable incomplete bowel movements, and my bad breath went away. Woohoo!!). I can't say that a low-FODMAP diet by itself did anything for my SD, but it did inspire me by showing me what a dramatic effect diet can have.
I did some research and found claims that people cured their eczema by eliminating nightshades from their diet. I realized that many of the same foods that people commonly report as triggers for their SD/PD are from the Asterid classification of plants (coffee, tea, peppermint, peppers - sound familiar?! Nightshades are included), or are related (e.g. most yeast comes from potatoes, apparently). I gave a shot at an elimination-style diet in which I avoid FODMAPs, refined Sugar and asterids, and the effect has been awesome. The redness is now only slightly visible (up-close and under certain lighting), the dryness is gone, and the flakes are nowhere to be seen, _as long as_ I stick to my diet. I'm only human, so occasionally, at a frequency of once every 2-3 weeks I'll eat one of the forbidden foods, and quite predictably the flakes come right back (usually the next day or so). When this happens I apply a little bit of the Aquanil and it subsides right away again. I've been doing this for a couple months now.
Writing all of this out makes me realize how fortunate I am, but obviously my SD is not completely cured, and I don't know how much of my success is attributable to the steroid lotion and to the diet. But I can say for certain that diet has had a tremendous effect, and my quality-of-life is much improved. At this point I'm experimenting with figuring out what other foods to eliminate in order to get the redness to completely disappear - the OP has inspired me to go get an IgE test done. Again, I'd love to hear from the OP or from other people about their experiences with diet and SD. If you want to talk in more depth about this, don't hesitate to email me: anjin65897 at gmail