A lot of us have been rubbing our eyes, sneezing, coughing, blowing our nose. You may have a summer cold or you may have allergies. It is hard to tell the difference, so here are the facts:

Colds are caused by hundreds of different viruses. When one of these viruses gets into your body, your immune system attacks it. Some of the effects of this immune response are the classic symptoms of a cold, such as congestion and coughing.

Allergies are caused by an overactive immune system. For some reason, your body mistakes harmless substances -- such as dust or pollen -- for germs and attacks them. Your body releases chemicals such as histamine, just as it does when fighting a cold. This can cause swelling in your nasal passages, a runny nose, coughing, and sneezing. Allergies are not contagious, although some people may inherit a tendency to develop them.