DD had what I thought was OAS, but skin tests to watermelon came back positive.  Last time she had it she kept clearing her throat.  Benadryl fixed that.

I have this problem with melons too (though in the past few years I can eat watermelon and honeydew as long as I'm on Claritin), as well as several other fruits and veggies (especially carrots, apples, stone fruits, bananas and kiwi).  I can eat them cooked though.  But I'm guessing cooked watermelon isn't too tempting to you, is it? 

However, like CM's DH, I've had severe reactions to cantaloupe.   I've never been tested, but the severity of my symptoms led my allergist to determine that cantaloupe is a true allergen for me, not OAS. 

While OAS rarely causes symptoms that are more than a nuisance, a small % of people can end up having serious reactions, so check with your allergist.

And feel better!

Let me guess-- you have a WICKED ragweed allergy, right?

The timing suggests that it's likely to be IgE-mediated somehow.  (Meaning it's allergy related somehow.)

It's sounds like classic oral allergy syndrome.  This is where your immune system mistakes a food for a pollen, basically.  It's usually not dangerous, but can be really aggravating to live with, as you know doubt are all too aware. 

Melons are a relatively common OAS offender, and a quite rare primary allergy.  This would be even more highly indicated if this is more severe (or maybe only a problem) at some times of the year-- for ragweed that would be late summer into fall in most places.

My first spouse, though, had a true anaphylactic allergy to watermelon, so it can happen.  Good idea to talk to your doc about it to be on the safe side. 

Has anyone ever hear or experienced this?

Usually after eating watermelon (or sometimes even grapes), my ear canals will feel somewhat blocked and very itchy. This usually starts occurring within 5-10 minutes after eating and lasts for about 10-15.

Would there be anything specific that is causing this?