A cold is a common viral infection that affects your head and chest. Even though it can make you feel miserable, it is not a serious condition and can usually be treated at home.
- A cold is a viral infection that affects your head and chest, including your nose, throat, sinuses and ears. A cold is not the same as influenza (the flu). Read about the difference between a cold and the flu.
- Cold symptoms develop slowly and usually last 1–2 weeks.
- Because a cold is caused by a virus, antibiotics won’t help (they kill bacteria, not viruses). However, there are things you can do to make you feel better.
- For most people, a cold will not lead to any more serious illness. Sometimes, however, you might get a bacterial infection after a cold, such as an ear infection or a sinus infection.
- You can treat most colds with rest and drinking lots of fluids such as water, but you need to know when to see a doctor.
What causes a cold?
There are over 200 different viruses that can cause colds. Cold viruses spread through the air when someone with a cold sneezes or coughs. You may also catch a cold by touching things that have been touched by someone with a cold, such as a door handle.
You’re more likely to get a cold if you:
- are tired, or emotionally or physically stressed
- do not have a healthy diet
- are a smoker or are exposed to second-hand smoke
- live or work in crowded conditions.
People appear to catch colds indoors during the colder months when living conditions bring people closer together and close to other people’s cold viruses. Closed windows and lack of fresh air also seem to contribute to the problem. Stress and cigarette smoking reduce resistance to infection and make symptoms more severe.
What are the symptoms of a cold?
Symptoms may include:
- scratchy or sore throat
- a cough
- sneezing and a runny or blocked nose
- watery eyes
- blocked ears
- a slight fever (37.2 to 37.8°C)
- tiredness and headache.
You usually start having cold symptoms 1–3 days after contact with a cold virus. The cold can spread to others even before any symptoms appear.
How is a cold treated?
The best way to treat a cold is to rest and drink plenty of fluid, such as water. You can also gargle salt water, sip lemon drinks or inhale hot steam.
There are no medicines that cure a cold. Because colds are caused by viruses, antibiotics will not help, as they kill bacteria. Taking antibiotics when you don’t need them is bad for you and causes antibiotic resistance.
However, you may feel better with medicines such as painkillers, nose drops or sprays, cough syrups and drops, throat lozenges and decongestants. Some are not suitable for children, babies and pregnant women.
Vitamin C does not prevent colds but may reduce the symptoms once you’ve caught a cold.
|When to see a doctor|
You won’t need to see a doctor if you have a cold, unless you have the following symptoms:
If your lips, skin or nails look blue, or you’re feeling confused, it is important to see your doctor as soon as possible.
How can I reduce my risk of getting a cold?
Regular hand washing, for 20 seconds with warm water and soap followed by 20 seconds of drying, is likely to be the best way to avoid catching a cold.
Other things you can do include:
- avoid close contact with people who have a cold
- keep your hands away from your nose and mouth
- eat a healthy diet
- get plenty of rest
- quit smoking
be physically active
There is some limited evidence that probiotics, vitamin C and zinc may also help prevent colds.
How can I prevent other people getting a cold?
It’s important not to spread your cold virus to other people. You can do this by:
- turning away from others and using tissues when you cough or sneeze
- washing your hands after coughing, sneezing or blowing your nose
- washing your hands often and especially before touching food, dishes, glasses and cutlery
- using paper towels in bathrooms
- not letting your nose or mouth touch public telephones or drinking fountains.
- not sharing food or eating utensils with others
- avoiding close contact with others for the first 2–4 days.
The following links provide further information about colds. Be aware that websites from other countries may have information that differs from New Zealand recommendations.
Coughs, colds and sore-throats – manage symptoms without antibiotics Choosing Wisely, NZ
Cold or the flu? Health Navigator, NZ, 2018
- Cold season in primary care BPAC, NZ, 2013
- Colds Ministry of Health, NZ, 2017
- Common cold Lung Foundation, Australia, 2013
|Dr Sharon Leitch is a general practitioner and clinical research training fellow in the Department of General Practice and Rural Health at the University of Otago. Her area of research is patient safety in primary care and safe medicine use.|