Last, but certainly not least to consider are diet possibilities. I've tried them all over the 10 years with a good trial run, and for 'me' they made no changes or differences at all and luckily I can eat anything.
But we've had some report good results by eliminating basics such as Wheat, (grains), Dairy, and Sugar, and within a short time they can see a difference, especially with eliminating the grains or Glutens.
No doubt at all, if one has Celiac or if you have a lot of 'gut' problems like Irritable Bowel or problems with constipation or diarrhea, Some take the Omega 3 oils, (I do) that can be wonderful for its many benefits for the whole body for anyone it's an excellent addition for overall health. EPO (Evening Primrose Oil), and Flaxseed have also been recommended. By the way, the EMU oil is high in Omega 3 and can also be purchased in capsules for internal usage.
Some have tried the Guaifenesin and Low Oxalate diets. (I did both and they made no difference) The low oxalate one hasn't been proven scientifically according to the literature, but eating certain foods, like greens, chocolate, berries, jello, beans and nuts, may produce oxalates in the urine that are irritating as the urine flows over that damaged tissue.
Eating less of these foods may help, but remember it's the tissue that's damaged and not necessarily the food you are eating if it never bothered you before, when even water or air flowing over it can irritate. Just as holding salt in your hand wouldn't burn or irritate but if you had a cut or wound of course it would. But the salt isn't the problem, the broken excoriated skin is.
By the way, many of those same foods I just mentioned might trigger a Herpes outbreak, in case you didn't know that, since many are high in Arginine. Herpes can often be contained quite well with taking the amino acid Lysine (also found in foods) to counter that breakout (avail. OTC).