Strep throat, which is caused by the bacterium group A Streptococcus, is formally called Streptococcus pyogenes (“pus-maker” strep).
While most sore throats are caused by viruses, this bacterium causes between 20% to 30% of sore throats in children. The ailment is commonly seen in children 5-15 years of age.
Group A strep is spread through droplets in the air from sneezing or coughing, drinking or eating after others who are contagious, and by touching a surface (or a rash) contaminated with it then touching the nose or mouth.
There is a two- to five-day period between exposure and coming down with the illness.
Symptoms of strep throat include throat pain, difficulty swallowing, swollen red tonsils (often with pus coating them), small red dots on the back of the palate (petechiae), and tender swollen anterior neck lymph nodes.
Other common symptoms include fever, headache, stomachache, nausea, vomiting and fatigue.
Strep throat can sometimes be accompanied by a sandpapery red rash that starts in the groin and underarm areas. This is known as scarlet fever.
Complications of strep throat can include sinusitis, otitis media (earache) and occasionally abscesses (pus pockets) around the tonsils.
The kidneys can occasionally become inflamed after an infection.
In certain individuals, group A strep can trigger an autoimmune condition called rheumatic fever. This can cause swollen, painful joints and damage the heart valves.
Some people are strep carriers – they may harbor group A strep in their noses or mouths that does not make them sick.
These individuals are unlikely to get any complications from it, but they can spread the bacterium to others.
Testing for strep throat is traditionally done by swabbing the back of the throat and then rubbing the swab on the back of a culture medium, which is incubated for 2-3 days to see if group A strep grows on it.
Rapid antigen tests can detect the outer coat of the group A strep bacterium. This is less accurate but takes only a few minutes to get a result. If it is negative, a backup throat culture is done.
Strep throat is treated with antibiotics, usually penicillin or amoxicillin. After 24 hours of treatment, the patient should no longer be contagious.
Antibiotic treatment usually makes people feel better sooner, decreases the time they are contagious and helps decrease the chance for complications. The course of antibiotics should be finished as directed.