You’re nose is runny and you have a cough. Do you have allergies or cold? It is hard to tell because they have very similar symptoms. But there are still some characteristics that distinguish the one from the other.
Overactive immune system causes allergies. The body mistakes the harmless substances as germs and attacks them. When the body is attacking, it releases histamine causing runny nose, sneezing and coughing. Allergies are not contagious but some people might develop them.
Colds, on the other hand, are caused by different germs and viruses. The body immediately attacks when one of these viruses enters the body and the immediate response of the immune system is coughing, congestion and runny nose. While allergies are not contagious, colds are. The viruses can be picked up from another person when he/she sneezes and coughs near you. When the immune system finally fights off the virus, you stop having colds.