First of all, excuse me if I make language mistakes, as english is not my mother tongue.
I want to share my experience with Seborrheic Dermatitis and how did I find the end of the constant suffer and pain that I experienced during a year/year and a half some time ago.
Two years ago, all of a sudden, I begun to have some red rashes in my face, nothing really serious (size of a peanut) but noticeable for everyone. As I have a very sensitive skin, I did not worry much about it, because I thought these rashes will be over in a while. That happened for a month or so until, after a big party night (where I drunk more than a couple drinks) I woke up with all my cheeks and jaw completely red. I was in shocked and I had to call my job to say that I could not go to the office as I felt bad. Luckily for me, it was a friday, so I had two days off to try to put down the eccema/general rash.
I went to a dermatologist next week and explain what happened (and show a little rash that I had) and she diagnosticated me of Sebhorreic Dermatitis. That was the beggining of a constant tour around visits and visits of diferents dermatologists (think I had visited 5-6 different ones) and every of them diagnosticated me the same: Sebhorreic Dermatitis. Every dermatologist said the same and receipted to me the different creams that we all known in this forum: Kenocotazole, Sebovalis, Ciclopirox, Zinc, Bioselenium, corticoids, even pimelocrimus (Elidel and so on). I literally try everything, spending hundreds and hundreds of Euros on creams and treatments that did not work. In fact, the rashes were worse and worse, with skin shedding, turning my face completely red. It was so embarrassing to go outside...I just wanted to stay home and hope that when I woke up the rashes were not visible any more.
During that time, I discovered this forum and begin to try the different solutions that I saw (honey masks, etc), but nothing seemed to work for me. At least, I got relief reading the testimonies of people that were in my exact same situation, that helped me a lot to not fall into desperation.
I decided to visit a last dermatologist that I found on Internet that had excellent reviews and was covered by my health insurance plan. When I got there I had a very several rash on my face, and I explained to him all my story: how I was being treated during the last 12 months with different creams and stuffs but nothink worked, and that all the doctors that I have visited said to me that I had sebhorreic dermatitis, that was something chronic and that the best results that I could have were to reduce its symptoms. He looked at me from a very close distance, and told me: I don't think it's sebhorreic dermatitis. Have you searched something on the Internet about it? Of course! Hours and hours trying to find some solution to that... He then pointed out something: It is very weird that the sebhorreic dermatitis are on all your cheeks, including neck and sideburns. I don't think it's Sebhorreic Dermatitis. Let's do this, we will do an allergy patch test on your back, and let's see if you react to the most common skin allergies.
For me that was a shock, as I was completely sure that I had Sebhorreic dermatitis, as 6 different dermatologists told me so! After a week carrying the patch test on my back, he confirmed his thoughts: I was allergic to Kathon CG -a commercial name for a Isothiazolinone-, a very, very common chemical biocide that was literally EVERYWHERE. (For more info search for "Isothiazolinone" in wikipedia). He told me to go home and check every label of every product that could have contact with my skin. Turns out that is so popular that was in my detergent, softener, washdisher, creams, soap...and in my aftershave (Nivea for Men). THAT WAS WHAT CREATED THE RASHES! It may seem silly, but I will never have found out if he didn't tell me, as was the aftershave that I was using all my life without any type of allergic reaction.
So, after a week of oral corticoids to put all the possible reactions down and throwing away all the products that contained Isothiazolinone from my house, I've been 1 year and a half free of rashes, eccemas or anything similar.
So, that was my case, and then I will recommend everybody that suffers more or less the same issues:
1) Don't surrender.
2) Go to a good dermatologists, with good reputation.
3) Ask him for a patch test to the most common chemical ingredients.
4) Try to relate your rashes to some product that you use and maybe you find out which is causing the skin reactions.