Colds, infections, flu and allergies all involve the immune system – the body’s mechanism for resisting disease and infection. The immune system produces antibodies to eliminate foreign substances.

In the case of a cold, infection or flu, the foreign bodies are harmful bacteria or viruses. The immune system attacks these invaders, which have the potential to harm the body.

In the case of allergies, the body mistakes a harmless substance, such as pollen or dust, for a dangerous invader. It then launches an attack that leads to the symptoms commonly associated with allergies.

Because these processes are so similar, the symptoms people experience with allergies often mimic those of a cold or infection. These include sneezing, nasal congestion and watery eyes.

Cold and flu symptoms generally resolve in a few days, once the body has successfully fought and conquered the invading organism. Allergy symptoms, however, may continue for as long as the person is in contact with that substance.

In rare cases, allergies can cause a severe allergic reaction (anaphylactic shock) that may result in hospitalization or even death. Therefore, it is important for people to consult a physician to determine the specific allergy triggers to which they are sensitive. Avoiding these triggers is the best defense for people with allergies.