What Causes Frequent Fever, Cold With Thick Greenish Discharge In A Child?

Hello, My son is 3 yrs 8 months old. (We moved from US to India when my son is almost 1.5 years). Since he is almost 1.5 years he had frequent fevers (almost every month or even twice a month). During which he was given antibiotics. Also during that time (1.5 years to 3 years) he was on ketamine, beclate - daily. He has erythema nodusm... which will be on and off most of the time - not continuous case. Beginning of this year, we visited ENT specialist. Who suggested to stop all the medication -but suggested that my son should do salt water gargling and inhale steam twice daily. Ever since the incidence of his fever frequency has come down significantly. But since few months he is continuously having cold, thick greenish discharge. During which he had fever once and was give antibiotics. Due to his continuous cold, we were asked to go for his blood test for the following parameters and I have put the results here. Hb: 11.6 WBC: 18700 DC - Neutrophils: 71% Lymphocytes:20% Eosiniphils: 9% Monocytes: 0.00 Absolute Eosiniphils: 1700. He weighs 13.1 Kg. Can any body suggest regarding his condition and medications? Thanks Shyam