Is this asthma?

I am treated for asthma with preventer inhaler.  I rarely need to use reliever inhaler.  I'm concerned that what I'm experiencing may not be asthma, although treatment works.  When tested with peak-flow metre, the test has been OK.  The 'asthma' attacks are very unpredictable and especially sudden. I don't wheeze. I am fine one minute and then suddenly all the tubes in my ears/sinuses 'seal up' and this sensation of swelling and blocking spreads to include lungs and I am gasping for air.  The reliever does help me get back to normal after a few minutes. What I can't understand is why I don't wheeze, though I have had coughing/irritability of the lungs when not using the preventer.  I also don't understand why these attacks are so sudden.  Recently, I was shopping and decided to pop into a natural health products shop.  I wasn't feeling stressed or anything.  After literally one minute in the shop, I could feel the tubes sealing up and myself getting breathless.  In the end I had to leave as I was struggling to talk.  It seems that something in the shop set it off.  This happens randomly in other places, and I have noticed it happen when a storm is approaching.  This seems weird to me and doesn't sound like asthma.  What do you think is happening?  I have had skin allergies and my mother is very allergic to insect bites and suchlike - she also recently had an anaphylactic attack after a bone marrow biopsy (thankfully clear), so the family background is there.

[National Jewish]

It is important to be sure of the diagnosis before making any specific recommendations. The diagnosis of asthma is not a difficult one to make. It is usually done by taking breathing tests before and after an inhaled medication. There are many reasons for sudden attacks. However, it is important to know what is going on to understand how to proceed. I would discuss the diagnosis with your doctor.

[leila]

Thank you very much for the response.  The diagnosis was made by asking questions and blowing into a peak flow metre (which I understand was fine at the time, and always has been on the 2 or three occasions when it has been given).  I did not have to inhale anything before the test.  The doctor has not witnessed any attacks, but has seen me coughing when my lungs were irritable before I went back on the preventer.  No-one has suggested any other form of diagnosis or suggested that there is any question about what was diagnosed.  I feel very awkward questioning the treatment I am getting, as the preventer does seem to help and the reliever does seem to work fairly quickly, though I still get these attacks.  It just doesn't sound like other descriptions of asthma that I've heard of.  Do you think I should pursue this?  I'm sure the doctor already has me down as a depressive and hypochondriac.  I have been diagnosed with chronic fatigue syndrome and some kind of nerve pain in my eye, face and head, for which I'm finally receiving treatment of amitriptiline (which provides a lot more relief than the 'dry eye' drops I was using before)!