Allergy- Excess mucous secretion

Hello All,
7-8 years back, I was allergic dust. I would sneeze every time I passed through dust. But, after some years it decreased. Now, some 2-3 years back, i am prone to a strange allergy. Wherein, there is excess mucous secretion in my throat. I contacted doctors, they gave medicine, until I take tablets it's not there, but once I stop taking tablets it again starts. The persistent cough itches all the time in throat.
I had also been to Ayurveda doctor, he says there is tiny nasal septum deviation and that is the reason for mucous generation. This irritation increases with drop in temperature, eating oily food and sometimes normal food also.
Even today I am struggling with this.
Could anybody help me out with this ? To avoid this I do breathing exercises, to clear my nasal tract, But still it persists.
Hope I get the solution for my problem
Currently my age: 24years

Regards,
Prajwal