A Red Peril

Q. Whatever happened to scarlet fever? It used to be a scourge of the young. Was a vaccine found? What about rheumatic fever?

A. Scarlet fever, which used to be called scarlatina, has not disappeared. The organisms that cause it, Group A streptococcus bacteria, still infect humans, and no vaccine is available, but it has become less common in the United States and much less serious, mostly because of antibiotics.

It seldom progresses to the serious heart-damaging complications known as rheumatic fever unless the patient neglects to finish a full course of antibiotics.

Scarlet fever usually begins with a case of strep throat, but can also start with a skin infection or surgical wound. In a fraction of cases, toxins from the infection cause a characteristic bright red rash that feels like sandpaper to the touch but is painless; it may eventually cause the skin to peel, like a sunburn.

The infection is easy to spread from person to person by way of mouth and nasal fluids, and the hardy bacteria can survive on surfaces and things like glasses.

Before antibiotics, scarlet fever patients were often quarantined, with a warning sign on the door, because epidemics caused high death rates.

The highest rate of infection is in children over 2 years who no longer benefit from maternal antibodies. As they become adults, most people develop immunity to the bacteria that most commonly cause scarlet fever. C.CLAIBORNE RAY

Drawing (Drawing by Victoria Roberts)