Diagnosis

Hello there...

I feel like i haven't posted on here in forever !!
I've been a little MIA this month because i have been focused on my health 

Can i just say, health is the most important thing you have, look after yourself :)

So lately i have been getting an intense reaction to something that no one can work out . It started about 7 years ago, one night i randomly started having trouble breathing, my nose was completely blocked, my throat got tight, I started coughing a lot & and my lungs felt really constricted. I had NO idea what was going on, i thought i was dying !  
I walked around my parents house & tried sitting in the outside air...next minute all my symptoms went away & the whole attack disappeared. The entire reaction lasted about 15 minutes but was the scariest thing i'd ever experienced.

Since that night, I've only had the attack about 6 other times & have spent years researching my symptoms & tried every single thing to determine the trigger. 
The last thing left to try was an asthma challenge test, which came back negative :( 

I feel like i'm back at square 1 again, i wonder if i'll ever work out what it is i'm allergic too 

Have you ever had an allergic reaction ? What caused it ?