My 19-month-old has been having running nose (yellow mucus) for four days and her voice seems hoarse, so I suspect a sore throat. Do I need to take her to the doctor for a strep test? She seems better, but I am concerned.

Strep is a bacterial infection of the throat that needs antibiotic treatment, even in an era when we are cutting way back on antibiotics. She is a bit young for strep to be likely. About 95 percent of people with strep are between the ages of 5 and 15, but those who are younger (and older) can certainly get it. The big things to look for include a fever, a sore throat that doesn't improve quickly, a tummy ache (maybe with vomiting), a headache, and possibly a sandpaper-like rash.

In my practice, I wouldn't call in for a visit a child of that age with a runny nose, a sore throat that is improving, and hoarseness (usually a sign of a virus, not strep)--unless the child had a temp over 101.5 or so, or unless there were a known strep exposure. Other indications to see your doctor would be signs of drooling or difficulty breathing.