Dust allergy may cause 1. Allergic Bronchitis 2. Allergic cough 3.May be triggering factor of Bronchial asthma You need to avoid dust as much as you can and boost your immunity to reduce allergic episode There are some supplement available that can be start after personal consultation and these supplement can reduce severity and no. of episodes of this problem You can take Vitamin C tablet, one tablet with food for 15 days Consult me for further management