Is it a Common Cold or Allergies?

It's a question that puzzles lots of folks when those familiar symptoms hit: Is all that coughing and sneezing from a cold or hay fever?

It's sometimes a tough call, but how long your problems last is one of the big clues.

What Are Colds and Allergies?

They have different causes. You get a cold when a tiny living thing called a virus gets into your body. There are hundreds of different types that can get you sick.

Once a cold virus gets inside you, your immune system, the body's defense against germs, launches a counter-attack. It's this response that brings on the classic symptoms like a cough or stuffed up nose.

The viruses that cause colds are contagious. You can pick them up when someone who's infected sneezes, coughs, or shakes hands with you. After a couple of weeks, at the most, your immune system fights off the illness and you should stop having symptoms.

It's a different story with allergies. They're caused by an overactive immune system. For some reason, your body mistakes harmless things, such as dust or pollen, for germs and mounts an attack on them.

When that happens, your body releases chemicals such as histamine, just as it does when fighting a cold. This can cause a swelling in the passageways of your nose, and you'll start sneezing and coughing.

Unlike colds, allergies aren't contagious, though some people may inherit a tendency to get them.

Differences Between Colds and Allergies

Take stock of your symptoms and how long they last to help you decide what's causing your trouble.

Characteristic

Cold

Allergy

How Long It Lasts

3-14 days

Days to months -- as long as you're in contact with the allergy trigger and a short time after

When It Happens

Most often in the winter, but possible at any time

Any time of the year -- although the appearance of some allergy triggers is seasonal

When It Starts

Symptoms take a few days to appear after infection with the virus

Symptoms can begin immediately after

contact with allergy triggers

Symptom

Cold

Allergy

Cough

Often

Sometimes

Aches

Sometimes

Never

Fatigue

Sometimes

Sometimes

Fever

Rarely

Never

Itchy, watery eyes

Rarely

Often

Sore throat

Often

Sometimes

Runny or stuffy nose

Often

Often

The most important difference is that colds usually don't last longer than 14 days. So see your doctor if you still have symptoms after 2 weeks. These may be allergy symptoms or signs of another problem.

Read more on: cold and flu, cold guide