Tips to help you distinguish a common cold from an allergy
The common cold can look and feel a lot like an allergy attack, but symptoms won’t improve with allergy medication. Here are some things to consider before deciding on the best course of treatment for your symptoms:
1. Nasal discharge
A runny nose due to allergies will usually produce thin, watery mucus. In contrast, nasal mucus will usually thicken over the course of a common cold.1 It may also become yellowish or green in colour. This is because your immune system sends white blood cells called neutrophils to the infected area, your upper respiratory tract. These cells contain greenish‐ coloured enzymes, which in large enough numbers can change the colour of nasal mucous.
2. The length of your symptoms
The common cold is caused by a viral infection of the respiratory tract3 and usually lasts only around three days to a week. More severe infections can last up to two weeks.1 If your symptoms persist beyond this timeframe, see your doctor. You may be suffering from allergies or an underlying condition that requires treatment.
3. The timing of your symptoms
Make a note of when your symptoms occur, as this may also help you to identify their cause. You might be more likely to suffer a cold when others in your family or workplace have recently been ill. Unlike a viral infection, an allergy will cause symptoms that recur in certain situations, or are persistent. For example, symptoms that occur every year at around the same time, such as during spring or autumn, may be due to hayfever (a pollen allergy).
The common cold or allergies will not usually cause a high grade fever or extreme fatigue. If you experience either of these symptoms, it is possible that you may be suffering from another type of viral infection, such as influenza.
If you have symptoms of a cold or flu that do not resolve within a reasonable amount of time, or are severe in nature, see your doctor for advice. He or she will be able to diagnose the condition causing your symptoms and advise you on its correct treatment.