I know a guy who would never eat pineapple on pizza, always claiming allergies to pineapple. I always thought that with food allergies, it is protein that is the culprit ie peanuts, milk, soy, seafood etc. I really don’t think pineapple has any protein and I am wondering if it is just an excuse.
I know some people are allergic to strawberries, and I think pineapple and kiwi are in the same family.
IIRC, it’s not a deadly allergy like peanuts, but causes hives and itching.
In my medical experience, 99% of claimed food “allergies” are not actually allergies at all. Rather, they’re either a dislike for said food, or on occasion diarrhea or malaise associated with eating said food.
Which is unfortunate, as it tends to minimize that 1% off the claims which are legitimate allergic reactions, and which can be fatal.
I just dragged a guy kicking and screaming from the brink of respiratory collapse yesterday, as he’d inadvertently eaten seafood unknowingly and was having intense difficulty breathing.
Having said that, there are documented cases of allergic reactions to pineapple. Bromelain is a proteolytic enzyme extracted from pineapple, and it has been demonstrated to cause an IgE mediated reaction in sensitive individuals.
My take on it: If someone claims they’re allergic to a food, don’t feed them that food!
BTW, your assertion that pineapple lacks protein is wrong. It doesn’t have a lot, but it has some protein.
One of which is the protease Bromelain. Some wild pineapples contain enough Bromelain to cause your mouth to bleed if you bite into them. Even the commercial fruit causes problems for some.
Strawberries, pineapples and kiwi fruit are related only insofar as they are all flowering plants. Kiwi fruit and strawberries are different dicot families and not closely related at all. Pineapples are actually monocots, making them about as unrelated to the other two as it’s possible to get.
A kiwi is a flightless bird, not vegetable, and is definitely not related to any of these plants.
I’m pretty sure we’re not suggesting that oral sex with a New Zealander is hazardous, either. 
Hence always talk of “allergies and hypersensitivities”.
I would think that if a particular food consistently gave you diarrhea you’d probably be better off not eating it, whether that qualifies officially as an allergy or not.
But try explaining all that to the average Joe.
I am well aware of the difference between my genuine food allergies - which cause hives, the Itch from Hell, strange urges towards purges, and breathing distress - and my “lesser afflictions” which “merely” result in three days of occupying the Littlest Room of the House with a number of magazines and a gross of toilet paper rolls. The former are Strictly Forbidden, the latter I can survive an accidental bite without requiring immediate medication.
But like I said, trying explaining that to the average Joe - who, I’m sure, is not THAT interested in my eating or excreting habits.
So I confess, I occassionaly use “allergy” to mean something not life-threatening, just really, really uncomfortable and miserable. Guilty.
And the next time some doc tells me “food allergies in adults are rare” or “it’s extremely unusal to have more than one food allergy” I am going to spit. Rare /= impossible. Guess I won the “allergy lottery”. I’m a walking wonder.
My father always said he was allergic to apples when I was growing up, and his mother confirmed it. He ate pears, though, with no problems, and could even eat dried apples. (I never knew what symptoms this “allergy” produced, though.) When I was in college, he started eating fresh apples again, and said that his “allergy” must have cleared up. (He’s a doctor, but a neurosurgeon rather than an allergist, so it’s possible it didn’t have a clue what he was really talking about.)
For myself, the taste buds on my tongue swell up when I eat pineapple. Whether or not it’s an official allergic reaction, it is painful enough that I tend to avoid pineapple unless it is well-cooked. (Cooked pineapple does it, too, but isn’t as uncomfortable.) I won’t die if I eat it (or at least, I haven’t yet), but I don’t choose to eat it if I have a choice.
I have the same reaction to raw tree nuts (walnuts and pecans). Cooked are fine, but if they haven’t been cooked, my little buds swell up and ache. I’m fine with peanuts, hazelnuts, and brazil nuts, though. Again, I don’t think I’ll die from eating them, and sometimes I even choose to suffer to enjoy them, but I tend to stay away from them if I have a choice.
When I was much younger, I thought that these were normal reactions to those foods. It wasn’t until I was in my 20’s, I think, that I found out it was unusual. I’m now in my 40’s, and I figure if I haven’t die from it yet, I’m not likely to.
Isn’t there some sort of bizarro cross ‘allergy’ between pineapple and latex?
Perhaps your non-pineapple eating guy was also allergic to latex? There is a demonstrated connection between people who have latex allergies and certain fruit and veggies. http://dmd.nihs.go.jp/latex/cross-e.html
http://www.pulmonaryreviews.com/jun02/pr_jun02_latex.html
A co-worker of mine is allergic, and she works in packaging in a pharmaceutical company. All other people working on the same line as her has to wear nitrile gloves just in case they brush against her skin (though I don’t know if her allergy is THAT severe, it was considered a safety precaution). She won’t eat things like pineapple, kiwi and strawberries, which appear to be very common culprits in latex-fruit reactions.
My son has life threatening nut allergies and we have had three panics so far in his nine years of life.
In the past few years he has also developed what the Japanese doctor painstakingly looked up and wrote down for me as “oral allergy syndrome”. When he eats raw apples, peaches and occasionally carrots, he gets very itchy in his mouth and throat and inside his ears. It goes away with an antihistamine tablet and time.
When I was a kid I had the same thing if I ate apples or cherries but oddly enough like the Dad mentioned upthread, I could eat pears.
Whatever it is that causes this can be destroyed by heat, so my son can eat applesauce, jam and canned fruit with no problems.
His dr says that this will probably lessen with age, but his nut allergy is likely to stay the same or get worse, and that allergy is not affected by whether or not the nuts have been cooked.