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Common cold or allergies?

Allergies can cause symptoms similar to those of a cold, but how can you tell if it is a cold or an allergy?

What are colds and allergies?

Colds are caused by over 200 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 nasal congestion.

The viruses that cause colds are contagious. You can pick them up when an infected person sneezes, coughs or shakes hands with you or if they are just in the air around you. Usually after a week or two, your immune system fights off the virus and you stop having symptoms.

Allergies are triggered by the immune system reacting to normally harmless substances, such as mould or pollen. Your body releases chemicals like histamine, just as it does when it’s 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.

Differences between colds and allergies






Up to 14 days

Days to months to years, as long as you are exposed to the allergen

Time of Year

Most often in the winter, but possible at any time

Any time of the year, although the appearance of some allergens is seasonal

Onset of symptoms

Symptoms take one to 3 days to emerge after infection with the virus.

Symptoms can typically begin immediately after exposure to the allergen
















Itchy, watery eyes



Sore throat



Runny or stuffy nose

Often; usually yellow mucus

Often; usually clear mucus


Although there are some differences, cold and allergy symptoms overlap quite a bit. The most important distinction is that colds don't usually last longer than 14 days. If you still have symptoms after this time, they may be allergy symptoms.

Colds and allergies: prevention and treatment

Because the causes of cold and allergy symptoms are quite different, preventing them requires different strategies.

To prevent allergy symptoms, avoid substances you're allergic to, called allergens, where possible. If you're allergic to pollen, for instance, avoid going outside on days when the pollen count is high. Here are some common allergens:

Although there are no guaranteed ways to prevent cold symptoms, you can try and minimise your chances of catching a cold. Keep your distance from people who have colds. Wash your hands often. To protect others, always cover your mouth and nose (with a tissue, rather than your hands) when sneezing or coughing.

There is no reliable cure for either the common cold or allergies although sometimes people appear to be cured of allergies or they improve with time. But there are ways to ease cold and allergy symptoms.

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