Allergic eye itching and cough.

Hi doctors My son has been suffering from eye infection for last 6-7 days. Itchy eyes and redness . We tried ciplox for 3 days. But didn't see any improvement. Itching is severe even after sleep he started rubbing . Eyes are not so red but not clearly white . But itching is there . No pimples or anything visible but some lines in sclera due to rubbing. And we went to doctor and give allegra syrup . It's 4 days but itching not improved so today he gave hista free eye drops. And since today afternoon, he started coughing like allergic cough without mucus . He suffered many time such type of cough. So can I give allegra suspension with histafree eye drops. And for allergic cough what to give. I think it is allergic rhinitis .