Hello, Cough due to eosinophilia is NOT a diagnosis as given by your physician. Although it is well known that eosinophil counts go up in asthma, allergies, parasitic infections; I am sure these have been checked and are not relevant here. You have not mentioned the absolute count or percentage but raised levels in patients with renal failure is mainly due to a vascular cause. If there is any skin rash, vasculitis is likely. If there are eosinophils in the urine, then the diagnosis is interstitial nephritis. Drug induced eosinophilia like interferon use should be considered if this drug was used, or for that matter blood pressure lowering agents such as ACE-I like enalapril, captopril, trandolapril cause chronic dry cough with raised eosinophil counts. A thorough review of the causes is required that should be addressed by your renal physician (nephrologist). I hope that was useful. Thanks.