Strep throat natural history

Complications
The symptoms of strep throat usually improve even without treatment in five days, but the patient is contagious for several weeks. Lack of treatment or incomplete treatment of strep throat can lead to various complications. Some of them may pose serious health risks.

Infectious complications

Noninfective complications
 * The active infection may occur in the throat, skin, and in blood.
 * Skin and soft tissues may become infected, resulting in redness, pain, and swelling. Skin and deep tissues may also become necrotic (rare).
 * Scarlet fever is caused by toxins released by the bacteria.
 * Rarely, some strains may cause a severe illness in which blood pressure is reduced and lung injury and kidney failure may occur (toxic shock syndrome).
 * During the infection, antibodies (disease–fighting chemicals) are produced. *Rare complication can result after the organism is cleared, when these antibodies cause disease in body organs.
 * Rheumatic fever is a heart disease in which the inflammation of heart muscle and scarring of heart valves can occur.
 * Glomerulonephritis is a kidney disease in which the injury may lead to kidney failure.