Ayurvedic medicine are the best treatment for allergic cough.
Need to know more history about your disease, this history is not enough for your problem.
You should take steam twice a day.
Take tulsi n ginger tea.
Giloy kadha because giloy is good immunity booster
Consult Ayurved physician for treatment with report n full history of your disease.
Next Steps
Investigate properly -xray chest, CBC blood test.
Health Tips
Yoga n Pranayama.
Avoid cold, oily, spicy,fast food.
Avoid banana,Curd ,rice n urad daal.
Take full precautions against allergens.
wear mask