My son started strongh cough and fever last week he' s taking pulmicort and micolyte and antihistamine but still what should i do?

Fever, dehydration: These start as viral infections, the worries come from 2ndary bacterial infection. Alternate doses of tylenol and ibuprofen (dont use other OTCs) every 4 hours and if he still has fevers higher than 100.5F (38C) after 24 hours, persistent vomiting, or profound diarrhea, see his doctor or go to the ER. Antihistamines won't help a 3 year old and side effects will confuse the picture. Hydrate!