Thanks for your question on Health Care Magic. I can understand your situation and problem. Eosinophils are marker of allergic disease. Their count rise in allergic conditions like asthma, skin allergy etc. Your son is also having chronic cough which is not subsided by routine medicines. So possibility of allergic cough due to asthma is more. So get done clinical examination of respiratory system by pediatrician. He needs anti histamine and anti allergic drugs. These will surely improve his cough and lower down eosinophil count. Hope, I have solved your query. Wishing good health to your son. Thanks.