A teenager at a downtown hotel had strep throat. Unlike most other bacteria, strep remains as sensitive to penicillin as it was seventy years ago. This is good news because penicillin is a terrific drug. It doesn’t upset your stomach, it has few side effects, it’s cheap….
“He’s allergic to penicillin,” said the mother.
“How do you know?” I asked.
She thought for a while. “The doctor told us. I think he had a rash…”
Once you’re branded as allergic to penicillin, no doctor in his right mind will prescribe it. This was bad news because I carry amoxicillin, a form of penicillin, and hand it out gratis. I don’t carry a substitute, so the mother had to find an open pharmacy and pay about twenty times amoxicillin’s price.
Ten percent of the population believes they’re allergic to penicillin and almost all are wrong. Ninety percent wrong is the usual figure, but some studies find almost zero genuine penicillin allergies.
What happened in this case? Chances are, years earlier the doctor prescribed a penicillin either to treat an infection or as a placebo, and the patient’s mother noticed a rash a few days later. Everyone knows that chicken pox and measles and rubella produce a rash, but any viral infection, including the common cold, can produce a pink, spotty eruption. To make matters worse, five or ten percent of everyone who takes amoxicillin or Augmentin (which contains amoxicillin) develops a similar rash. It’s harmless and disappears in a few days. Stopping the antibiotic doesn’t speed this up.
Experts agree that none of these are allergies.
But why take a chance? Laymen worry. It’s 100 percent safe (and much quicker) to diagnose an allergy.
If a doctor had told you to flush $1000 down the toilet, you’d object, but that’s the equivalent if you go through life with a nonexistent penicillin allergy. If you’re lucky!... Rarely, you could be in serious trouble.
Skin tests are accurate, so you might want to see an allergist. It costs a few hundred dollars which insurance might not cover.