Do you have any "real" allergies?

Up until Saturday afternoon I had no known allergies, but I did have a stonking headache! I called the wife and whilst she was out she picked me some medication up. This medication was nothing new to me so I popped two Nurofen Express (other meds are available) and settled down waiting for them to work I knew it would take an hour or so from the last time I had some.
After an hour had elapsed I started to get a rash on my neck which soon spread to my entire body, my face swelled up, lips went numb and voice deepened!
I went straight to A&E (ER) and they sorted me out and kept me in till the next morning.

My question is this: Do you have any “real” allergies?
Non of this I don’t like cats lark or foods you just detest.
I used to think I was allergic to boiled mussels but no, I simply don’t like the taste and it makes me vomit!
I now know what a proper allergy is and it is not nice! No more Non Steroidal Anti-Inflammatory Medication for me.