The number of tonsillectomies has steadily declined because of new and potent antibiotics and prompt recognition and treatment of tonsillitis.

About 120,000 tonsillectomies were performed in the United States in 1989 - slightly less than half the number performed in 1980."While tonsillectomy is minor surgery, it does involve a small risk, which increases with a patient's age," said Dr. Hosakere Chandra Sekhar, an ear, nose and throat specialist at New York University Medical Center. "The procedure is not performed routinely."

If a child has several attacks of tonsillitis in a year, develops an abscess on the tonsils, or if breathing or swallowing is impaired, removal may be required, Chandra Sekhar said.

"A sore throat in young children should be evaluated promptly because of the possibility of serious complications," the doctor said. Untreated, a strep infection can lead to serious health problems, such as rheumatic fever, an inflammation of the heart or glomerulonephritis, an inflammation of the kidneys.

The two tonsils, which are lymph tissue at the rear of the throat, reach full size during childhood, then gradually shrink. While tonsils help fight infection, they are themselves prone to infection.

Tonsillitis in young children is often accompanied by inflammation of the adenoids, lymph tissue above the tonsils which are full size in children but begin to shrink around the age of five and atrophy after puberty. Adenoids also help the child resist respiratory infections.

If tonsils are removed, adenoids are often removed at the same time.

"A throat culture should be performed on anyone with a sore throat to determine the cause of the inflammation," Chandra Sekhar said.

If the infection is caused by streptococcus bacteria, it can usually be treated effectively with an antibiotic, such as penicillin.

Tonsillitis is most likely to occur in children aged 3 through 10.