thanks for your query, High levels of eosinophils indicate there is an allergic process is certainly going on. The cough
symptom which aggravates at night to me is consistent with this. Would also be interesting to know if you got any family history of asthma
I would suggest you do a chest X ray
and spirometric examinations. A peak flow to rule out asthma could be worth while.
Consulting a pulmonologist/internist could be ideal in ruling out formerly an allergic component in your symptoms and working towards a definitive working diagnosis.
Thanks and hope this helps,