OAS vs. LTFA: What's the distinction?

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Mookie86:
Having recently realized that I have OAS, I'm struggling to understand it. We tell people with nut allergies that there's no such thing as a minor allergy to peanuts or tree nuts, and that one reaction does not necessarily predict the next one. I have seen many people be advised that, even if it's only an itchy throat that subsides on its own or with an antihistamine, next time it could be a full-blown, life-threatening reaction. Why is the identical reaction to an apple viewed as mere annoyance and not potentially serious? I know that you can be LTFA to fruits, so how is that different than OAS?

hopechapel:
ditto the confusion. awaiting the replies.

The Dr. thinks my son's reaction to walnut is OAS. She did not keep challenging because she did not want to mess up the hazelnut pass. But his mouth was itchy. When he described his reaction to our friend and neighbor he said his mouth got itchy and his throat got tight.

Thoat got tight ??

She also thought he might have an itchy mouth with raw hazelnut and that both could be attributed to his pollen allergy. She does not want him to eat nuts at school because f he were to have such a reaction it would confuse them. WTF? It would confuse me too. I think I have a handle on all this and I don't.

MamaMia:
I understood that OAS is related to pollen allergy, what they call cross-reactivity & one can only be allergic to raw fruit and veggies (but nothing else). Baked in fruit or cooked veggies don't seem to cause problems. OAS only affects certain areas but "rarely" lead to respiratory problems (ana). Areas affected can be ithcy mouth and tongue and sometimes hives around mouth.

Here's a great explanation from CHOP (great chart too):
http://www.chop.edu/service/allergy/allergy-and-asthma-information/oral-allergy-syndrome.html

rebekahc:
DS has OAS to bananas. Our allergist advised us that OAS can be just as serious as true food allergy because the swelling in the mouth/throat from OAS could still obstruct the airway.

I think the biggest difference is that with OAS, a person might be able to tolerate the food peeled, heated, not in pollen season, etc. and is likely only to react upon major ingestion. No need to worry about it in the environment or cross-contamination, etc.

CMdeux:
My understanding is that to some extent, once a person has a demonstrated ability to anaphylax, then it doesn't really matter what the "nature" of the trigger happens to be.

So in someone with environmental allergies and OAS... it may be fairly mild and not something to "worry" about in that direction.

On the other hand, in someone who has been intubated for a shellfish or insect venom reaction? Birch pollenosis (OAS to apples, etc.) may well be much more serious.

If it can trigger symptoms at all, basicaly, then it is tinkering with that mast-cell cascade.

So I'm not sure that there is a clear differentiation in a person who has had anaphylaxis to another allergen.