I had the surgery in 1995 and had no skin issues until a few years ago. It seemed to come out of nowhere and was miserable, red/raw. I asked my doctors about it (G/I, internist, dermatologist and even my gynecologist). A second dermatologist tried several things with me and finally sent me to an allergist. It turns out that I am allergic to tomatoes, as well as several other things!
I'd estimate that I am now 80-90% better. Three things that have helped me a lot:
1. I don't eat tomatoes although I still consume some of the no-no's that don't bother me as much, including black tea and chocolate - I'm willing to live with the irritation in exchange for being able to consume them. My overall skin is less irritated now that I have changed this part of my diet, although I never had any significant skin problems besides the perianal area.
2. I apply vaseline before I defecate. It acts as a bit of a barrier. (I tried Calmoseptine and thought it was miraculous...at first. After using it for a week or so, it started to break down my skin, making things much worse than my original problem).
3. I ideally take a bath (soak) before going to bed each night. Second choice is to use a spray attachment in the shower, again before going to bed. I was surprised how much this has helped.
BTW, I'm not suggesting that any of you are specifically allergic to tomatoes. I just wanted to point out that something beyond multiple daily bowel movements may be causing skin irritation .