My grandchild has a cough going on two years what could this be?

Allergy, asthma, CF?: The primary care doctor should evaluate first. A child can also see an allergist because allergists usually are specialized in the areas of asthma as well as allergies. A pulmonologist (lung doctor) can check for less common disorders (like cystic fibrosis), as well as give an opinion on the coughing. In a few cases, there are problems in the voicebox area or in the trachea (ent doctor can check).