Typically the difference between a cold and allergies starts with the causes for each and the duration. A cold is an infection resulting from a virus. An allergy is your body’s reaction to certain substances that it views as an invader and triggers your immune system into action. A cold will usually last for anywhere between a week to 10 days while allergies continue for an indefinite period of time while your body is exposed to the trigger. Here are some symptoms to help you determine if you might have a cold or maybe an allergy to something.