Strep throat, caused by Streptococcus pyogenes (Group A Streptococcus), is a common bacterial infection that manifests as a sore, scratchy throat. Unlike many viral sore throats, strep throat requires antibiotic treatment. If left untreated, this infection can lead to serious health complications throughout the body. Understanding these potential consequences highlights the importance of timely medical intervention.
Local Complications and Progression
When strep throat remains untreated, the infection can worsen and spread to tissues surrounding the initial site in the throat. This localized progression can lead to the formation of abscesses, which are collections of pus. These include peritonsillar and retropharyngeal abscesses.
A peritonsillar abscess forms behind a tonsil, causing severe pain, difficulty swallowing, and a muffled voice. Swelling near the tonsil can become visible. Retropharyngeal abscesses, though less common, form deep behind the throat. They cause intense pain, difficulty swallowing, and noisy breathing, posing a risk of airway obstruction. If these abscesses rupture, the infection can spread further, potentially leading to pneumonia.
Rheumatic Fever
One of the most concerning systemic complications of untreated strep throat is rheumatic fever. This inflammatory disease affects various body tissues. It is an autoimmune reaction where the body’s immune system, attempting to fight Streptococcus pyogenes, mistakenly attacks its own healthy tissues. Symptoms typically emerge two to four weeks after the initial strep infection.
Rheumatic fever can cause inflammation in the heart, joints, brain, and skin. The most severe long-term consequence is rheumatic heart disease, involving permanent damage to the heart valves. This damage can impair the heart’s ability to pump blood effectively, potentially leading to heart failure years later. Individuals might also experience painful, swollen joints, often migrating from one joint to another. Other manifestations include a non-itchy rash known as erythema marginatum and involuntary, jerky movements called Sydenham’s chorea.
Post-Streptococcal Glomerulonephritis
Another serious systemic complication from untreated strep throat is post-streptococcal glomerulonephritis (PSGN). This condition involves inflammation of the tiny filtering units within the kidneys, known as glomeruli. PSGN develops as a delayed immune reaction, typically occurring one to two weeks after a strep throat infection.
The inflammation in the glomeruli impairs the kidneys’ ability to filter waste and excess fluid from the blood. Common symptoms include dark, tea-colored urine due to blood, and swelling (edema) around the eyes, face, hands, and feet. Individuals may also experience high blood pressure and reduced urine output. While many people, especially children, recover fully, some cases, particularly in adults, can progress to chronic kidney disease or kidney failure.
Other Serious Complications
Untreated strep throat can lead to additional, though less common, serious complications. One such condition is Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections (PANDAS). PANDAS is characterized by the sudden onset or worsening of obsessive-compulsive disorder (OCD) symptoms or tic disorders following a strep infection. This is thought to involve an autoimmune response where the immune system mistakenly attacks healthy brain tissue.
Streptococcal toxic shock syndrome (STSS) is a rare but life-threatening complication. Caused by toxins released by Streptococcus pyogenes, STSS can lead to rapid onset of fever, muscle aches, low blood pressure, shock, and multi-organ failure. This condition requires immediate hospital care and aggressive treatment. The bacteria can also spread to cause severe skin and soft tissue infections like cellulitis or, rarely, necrotizing fasciitis (“flesh-eating disease”).
The Importance of Timely Treatment
Early diagnosis and appropriate antibiotic treatment are highly effective in preventing serious strep throat complications. Administering antibiotics within 48 hours of symptom onset can significantly reduce the duration and severity of the illness. This also prevents the development of conditions like rheumatic fever and kidney inflammation. Completing the full 10-day course of antibiotics is important to ensure complete eradication of the bacteria and minimize the risk of complications and recurrence.
Individuals experiencing symptoms such as a sudden sore throat, fever, difficulty swallowing, or white patches on the tonsils should seek medical attention promptly. A rapid strep test or throat culture can confirm the presence of Streptococcus pyogenes, allowing for timely initiation of treatment. Swift action alleviates immediate symptoms and protects against potential severe, long-term health consequences.