Is it possible to have no trigger asthma?

I have been checked by the medical profession for a couple of years to see if they can find a trigger for my asthma and have not been able to? I got asthma though hayfever. I still suffer with hayfever but doesn't trigger an attack in anyway. I am on fostair and I have not had 1 attack in 3 years maybe 4

[Minushabens]

I think it's now generally understood that asthma isn't a single illness nor has a single cause, but can have multiple origins. The most common one I think is atopic asthma (allergic) which tends to be the version that develops in childhood, but there are other variants. So, I suppose yes it's possible...although I'm not an expert!

[Superzob]

Atopic means an allergic reaction without contact with an allergen. There are a number of atopic diseases, including asthma and dermatitis. My late onset asthma may have been the result of having hayfever for 50 years, and I am allergic to pollen. However, the asthma is constant, whereas the hayfever is seasonal. Oddly enough, if I take Beclometosone nasal spray in winter, it seems to reduce my incessant winter colds, which seem to be a symptom of poor lung function due to the underlying asthma and, in my case, fixed small airways obstruction.

So, yes, you can have asthma without contact with an allergen and there does seem to be a link between hayfever and asthma.