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Yes, you can give. But, I would recommend syrup Wikoryl-AF (Chlorpheniramine maleate and Phenylephrine) 5 ml 3 times daily for five days or syrup Allercet (Cetirizine) 5 ml once at night time for five days. Also, one teaspoon honey at night. Consult your specialist doctor, discuss with him or her and take medications with their consent.
But, if he is breathless, you would require seeing your doctor for nebulization, etc. Honey works wonderfully and safe also.
For more information consult a pediatric allergy asthma specialist online --> https://www.icliniq.com/ask-a-doctor-online/pediatric-allergy-asthma-specialist