Colds and Asthma

Health Professional

With cold weather coming upon us (in many parts of the country), it is the time of year that adults and children are getting more colds, and this can affect peoples' asthma. I'd like to go over a few thoughts about the effects of colds and asthma in this entry, focusing on strategies to avoid getting colds and asthma management when we catch one.

What causes colds?

Over 90% of common colds (upper respiratory infections, 'URI's) are caused by cold viruses. These viruses are easily transmitted from person to person, at home, work, school, and in the child-care setting. People typically start with a runny nose, a scratchy throat, and can feel run down with an occasional low grade fever. Cough usually develops later, and symptoms typically last 5-10 days, after which things clear up. Very few URIs are caused by bacteria. This is also true of sore throats without runny nose ('pharyngitis'). Only about 15% of pharyngitis is caused by bacteria ('strep throat'), which does require antibiotics.

Avoiding getting colds

We were always taught to cover our mouths when we cough or sneeze, especially when we have a cold. While this is certainly good manners, most colds are not caught by breathing in infected cough or sneeze droplets of others, but rather by direct contact. Since we are always (and unconsciously) touching our mouth and nose, small amounts of these secretions are almost always on our hands. Since cold viruses can live happily outside our bodies for several hours, we inadvertently pass them onto things we touch as part of daily living - door handles, faucets, kitchen items, among others. When someone else opens the same door a few minutes later, for example, they come into contact with virus. When they next touch their nose or mouth, they are probably exposing themselves to virus. This is why we can easily catch a cold without remembering being around someone who was coughing or sneezing.

While it is a good idea to cover our mouths when we cough or sneeze, we can go a long way to limiting the spread of colds by frequent hand washing with water or mild soap. For obvious reasons, this is hard to do with kids - and part of the reason why kids are more susceptible to catching colds.

Colds and asthma

For reasons that are still being carefully studied by scientists, URIs, especially those caused by viruses, account for the majority of asthma exacerbations in adults and children. Some patients with asthma can feel a cold coming on because they feel chest tightness and wheeze before they have a sore throat and runny nose. Worsening of asthma control should be treated the same as other asthma triggers - continuing your controller medicine (or increasing it as recommended by your doctor) and using quick relief medication as needed. Of course, the best way to avoid a flare from a URI is using the precautions mentioned above to not get a cold in the first place - though not always as easy as it sounds.

Final thoughts

A brief word about antibiotics and colds... Many people, both with and without asthma, are concerned when cold symptoms last longer than 3-4 days and have persistent cough: "This cold has settled down in my chest." Cold symptoms and cough can last for 10 days in some individuals. Often this will lead patients to feel that they need antibiotics to help 'clear it up.' Since over 90% of colds are caused by viruses, antibiotics are rarely indicated, and are of little value in this setting. Unnecessary antibiotics can upset the normal balance of healthy bacteria that live without causing problems both in our intestines and on our skin. Antibiotics should be reserved for when symptoms clearly suggest a bacterial infection. With a little patience, you should be over your cold without medication that does little to help your body's natural defenses. Of course, your primary care physician can help you navigate your specific situation.

Some links you might find helpful:

Understanding Asthma

Respiratory syncytial virus (RSV)

Asthma Complications