I occasionally get cracking in the corners of my mouth whenever I eat any foods with vinegar or soy sauce. This is because they both contain yeast which causes chelitis. I avoid using these ingredients and all yeast but sometimes it's unavoidable. I also get redness above my upper lip.
For the cracking I use a little of the cream I get with my yeast infection treatment capsules. It is a miconazole 2% cream. Within 1 -4 days the cracking and redness is gone without fail. It really works. I apply it morning and night.
For my upper lip redness I use a common clotrimazole cream used for athelete's foot and an antibacterial non steroid cream from my doctor and apply them both to the affected area four times a day. I also tone my face and upper lip with pure witch hazel and a few drops of tea tree oil every second night or so, rinse it off and use no moisturizer. I also avoid all yeast foods. This works after about 4-10 days and after a few treatments of this the redness now is virtually gone. It will return if I eat more yeast containing or causing foods but now goes away on its own after a few days when I stop. I will appply the atheletes foot cream a couple of times a day to speed up the process.
I also eat a very healthy vegan diet with no sugar, salt or yeast and take a vegan yeast and salt free vitamin and 2 500 mg l lysine capsulses a few times a month. This all has really done the trick for me and I can now happily say I am no longer bothered by this upsetting ailment.