Is It Strep Throat?

A sore throat is one of the most common reasons for seeing a doctor. Most of the time the cause is viral, and you can ease your suffering with chicken soup and a painkiller like acetaminophen. But sometimes the problem is a kind of bacteria called group A streptococcus or strep, for short. That's when antibiotics like penicillin or erythromycin come in handy. Early spring is a peak season for strep throat. If you have a sore throat that is accompanied by a fever but not a cough, your lymph nodes are swollen and there are yellow or white patches on your tonsils or the back of your throat, chances are, you have strep. The trouble is, most people with strep don't get all those symptoms. (A sore throat plus a runny nose and cough is usually just a cold.) It's not always easy even for doctors to tell the difference between viral and bacterial infections on the basis of symptoms alone.

Or at least that is one of the conclusions of a study published in last week's Journal of the American Medical Association. When doctors at a family-medicine clinic in Calgary, Alta., depended on clinical observation to determine whether or not a patient with a sore throat needed antibiotics, they guessed wrong 40% of the time making the kind of error that only furthers the spread of drug-resistant diseases. Doctors got the best results if they relied on a microbiologic lab test either a two-day throat culture or the somewhat less accurate 20-min. rapid test.

For decades, the main reason to treat strep throat was to make sure it didn't turn into rheumatic fever, a serious illness that can damage the heart. The rule of thumb here is to give antibiotics within eight or nine days of the onset of symptoms, which is why you can afford to wait for the results of a throat culture. For reasons that are not clear, the incidence of rheumatic fever has dropped dramatically in most of the U.S. since the 1930s. And studies have shown that many adults get over mild strep infections without taking antibiotics. Children, who are more susceptible to strep and rheumatic fever, are usually treated more aggressively.

So be patient if your doctor swabs your sore throat or your child's instead of immediately prescribing antibiotics. That will increase the chances that the drugs will still work when you really need them.