The most serious complication of tonsillitis is
rheumatic fever, which often is accompanied by rheumatic heart disease. Rheumatic fever develops only if the tonsillitis is due to a type of bacterium known as group A beta hemolytic
- streptococcus. It also usually occurs only in children who have had repeated infections that have not been adequately treated with antibiotics.
Another complication of streptococcal tonsillitis is a type of kidney disease known as
acute glomerulonephritis. However, whether glomerulonephritis can be prevented by early antibiotic treatment of streptococcal tonsillitis is not clear.
A common complication of tonsillitis is infection of the lymph nodes in the neck, known as cervical adenitis. This type of infection can usually be successfully treated with antibiotics. Occasionally the infection progresses, an abscess forms, and surgery is required to drain it.
Other possible complications of tonsillitis include middle-ear infections (otitis media) and sinus infections. More often, however, these infections develop at the same time as, or independently of, tonsillitis.