Breath of Fresh Air: Feature Articles

Chapter 43: How can I tell if I have the flu or "just a cold"?

The flu is a respiratory infection caused by the influenza virus. In many ways, the flu can feel much like infections caused by common cold viruses. It causes fever, sore throat, nasal congestion and drippiness, and a troublesome cough. The cough may be dry or may cause one to cough up a clear or whitish phlegm.

Illness caused by the influenza virus is often more severe, however, than the usual winter cold. Typical of the flu are severe muscle and joint and back pains. One feels achy and sore all over. Fever may be particularly high and long-lasting in the flu. With it may come an overwhelming sense of exhaustion and weakness, with loss of appetite.

A particularly severe cold with muscle and joint aches in the middle of flu season will make your doctor suspicious of an influenza infection, especially if you have not been vaccinated with the flu vaccine. It is difficult for your doctor to be certain about a diagnosis of the flu. A special culture can be obtained from the back of the nose in an attempt to grow the influenza virus in a diagnostic laboratory. Blood tests can be done during the illness and two weeks later to look for the antibody proteins made as part of the immune system's reaction to the influenza virus, but the results of the blood tests will come too late to be much use to you. New, rapid diagnostic tests performed on nasal or throat swabs or on expectorated sputum have just recently become available (see News about Asthma feature, Chapter 50).

The usual treatment for chest infections caused by viruses is to get plenty of rest, maintain adequate fluid intake, and take acetaminophen (Tylenol®) or other over-the-counter cold remedies to reduce fever and relieve aches and pains. Antibiotics used to treat bacterial infections are of no use against viruses, but new anti-viral medications are now available that can shorten the duration of flu symptoms by a day or two (also described in a News about Asthma feature, Chapter 50). These medications against the influenza virus are likely to be particularly useful during known outbreaks or epidemics of the flu such as in a school, nursing home, or local community.

Many over-the-counter cold remedies are marketed specifically for the flu. In fact, they are no different than other combination over-the-counter cold remedies. Most contain — in various combinations — an antihistamine (such as chlorpheniramine), a nasal decongestant (such as pseudoephedrine or phenylpropanolamine), a cough suppressant (such as dextromethorphan), and a fever reducer (such as acetaminophen). Scientific studies have found that herbal remedies, such as echinacea or elderberry extract, are not of benefit.

It remains true that one's best bet for never getting a respiratory infection caused by the influenza virus is to get vaccinated against the flu each fall. The flu vaccine has been carefully tested and shown not to cause asthma to worsen.