Anything is possible, and while you could be sensitizing to peanut there's several reasons I'd think not.
First, most adults don't sensitize to nuts later in life. They can, but shellfish or crustaceans are the usual culprits. Peanut butter is the last thing I would suspect if you were truly sensitizing to peanuts. Peanuts are pretty much everywhere in food across Taiwan. Yes, I'm very familiar with Taiwan in particular. Peanut butter is harder to find than ground peanuts or boiled peanuts that's in much of the food. Even 沙茶醬 comes in a variety with peanut in it and 沙茶醬 is used in so many foods.
Even still -- It's specifically peanut butter (and sometimes just plain peanuts) that sends me running to the bathroom and likewise makes my stomach ultra bloated / gassy for hours. I ate 2 peanut butter sandwhiches for lunch at 2 PM. It is now 3 AM... and my stomach has been keeping me going since 9:30 PM.... and I'm still awake because of it. Seafood I can eat. No hives, no rashes, no problems. But Jiffy... or just plain salted peanuts... and ouch.
The medical system there is quite affordable without insurance, we've used it before for ourselves and for our child. That said you have to know people who know the right people to get to a good doctor. Taiwan is actually the center of a lot of solid IgE-mediated allergy research hosting the APCAACI conference in 2013.
I do know it's a good system... but my Taiwanese wife and I are living on a single income (hers) and that limits our options. It took me 5 years to get my ARC. (No kidding.... 5 years... We had to actually go through a government elected official on a specific committee in order to to by-pass imigration. No fooling.) It cost us several thousand (US) of our savings just to get that done. Because I don't have a college degree ---- no work for the last 5 years. It's only been the last 8 months that I've been able to legally work. Sooooooo.... we're only just now back to saving $$$$ and we're gonna be applying that first to long-term health care insurance. Allergies are low on the priority list, hence why I'm net-searching for answers.
I can get the name of a well qualified allergist there if you want to get started. Hong Kong would be another option if you're paying out of pocket anyhow and since you're an American my understanding of our responsibilities living expatriate is that we still owe taxes 'here' so you may be able to write that off partially as medical expenditure.
The wife is sensitive to this. She's pure DPP blue... if you know what I mean. To her, the KMT are devils who invaded Taiwan and should all be expelled. Thus --- Hong Kong is not an option. Mention China in her presence and she's libel to sit you down and grill you on your loyalty to her nation.
But there's a point here that I can help you on.... The IRS does not require anyone living abroad to file taxes, so long as they are under $80,000 US (per person filing, so if jointly, $160,000) in earned income on foreign soil. This is not myth or rumor --- you can find this information directly at the IRS.gov website. I researched the matter myself.... and likewise inquired of several tax lawyers on the matter. It's a little known fact and it's helped us to plan our finances better. ----->> edited additional info ---->> the only requirement is that you live outside of the USA for a total of 305 days in a calendar year. I haven't been back to US soil since 2010... so no real issue there.
For peanut what I would be concerned about are really nasty bacteria. Even in the US the peanut industry here has caused horrific public health issue do to outrageous sanitary conditions that killed some, sickened many more. Honestly, if you're eating like a local you're probably eating a lot of peanut all the time.
Yea, aware of the adoration of the peanut in this culture. I've made many a joke about it. Nevertheless .... whether its Costco bought Jiffy PB .... or local store bought, Taiwan-grown peanuts in a shell.... it's the same reaction. Diarrhea, bloating and gas. (and occasional belching. forgot about that.)
I'm probably the only regular on FAS that has specific knowledge of where you currently reside, FYI.
I fell in love with Taiwan when I came here to ask my wife's father's blessing upon our marriage. 5 days after I got here, I made the decision to reverse my plans to move my wife to America. I have not regretted that change of plans for a single day. Amazing country. Wonderful people & culture. And a wealth of opportunities. I tell folk all the time that it's like living in 1950's Mayberry. (The Andy Griffith Show) ---- (some) People leave their keys in their scooters overnight.... I mean, seriously... it's just that polite. But you know what I mean.
how long were you here?