 [ Symptoms ] how can i tell if my child has allergies or a common cold [ Disease ] symptoms of allergies and colds can be similar but here is how to tell the difference occurrence of symptoms both cause symptoms of sneezing congestion runny nose watery eyes fatigue and headaches however colds often cause symptoms one at a time first sneezing then a runny nose and then congestion allergies cause symptoms that occur all at once duration of symptoms cold symptoms generally last from 7 to 10 days allergy symptoms continue as long as a person is exposed to the allergy causing agent but may subside soon after elimination of allergen exposure mucus discharge colds may cause yellowish nasal discharge suggesting an infectious cause allergies generally cause clear thin watery mucus discharge sneezing sneezing especially two or three times in a row is a more common allergy symptom time of year colds are more common during the winter allergies are more common in the spring through the fall when plants pollinate presence of a fever colds may be accompanied by a fever but allergies are not usually associated with a fever