I've gotten a rash on my lips 3 times in the last 6 months, even though I've never had any problems with skin allergies before. The first two times I assumed it was poison ivy, transferred from my outdoor cats to my hands to my mouth. It's very similar to that type of rash - small, dry, whitish bumps that tingle and itch quite a bit. They're barely visible on my lips and redness isn't evident because of their location. There's a little dryness, itching, and slight redness to the sides of my mouth as well, but no bumps. The rash is only on my mouth this time, while the other two times I had a few bumps on my arms as well. I haven't come in contact with outdoor cats or poison ivy/oak in ANY capacity this time, so it can't be that. Could it be some sort of cat dander/saliva/urine allergy that only manifests occasionally? I just got a new kitten, but I spent most of the past 6 months living in a house with 4 or more cats and only had the rash twice (for about a week each time). I've also had cats for 10 years and never had any allergy issues before. I know new allergies can develop as you age (I've developed a localized allergy to wasp stings in the past few years), but this only shows up occasionally. Does anyone have any ideas or experience with this? EDIT:
Upon further scouring of the internet, I think I've figured it out. I'll leave my post up to help anyone else who might have the same problem.
I'm almost positive that the rash is allergic contact dermatitis to mango rind. According to W.ikipedia:
The mango is in the same family as poison ivy and contains urushiol, though much less than poison ivy. Some people get dermatitis from touching mango peel or sap.
I've been allergic to poison ivy/oak all my life, and I just happened to eat mango right off the rind on Tuesday (the rash appeared on Wednesday). So it seems the mystery is solved!