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Strep throat is the most common of bacterial infections, accounting for about 15% of all sore throats that get diagnosed in the doctor's office. It's most common in children, but many adults get strep throat, too.
It's called "strep" throat because the bacterium that causes it belongs to the class known as group A streptococcus (GAS). The initials GAS are sometimes used, and doctors may talk about a GAS throat infection. Although strep throat can occur any time during the year, late winter and early spring are considered to be peak seasons for strep throat infections.
Sore throat is one of the leading complaints that bring people to the doctor's office, and about 40% of sore throats are treated with antibiotics in Canada. In fact, fewer than half of the people given antibiotics actually have bacterial infections. Most of the rest have viral infections that are not affected by antibiotics.
When used appropriately, antibiotics are very helpful in fighting infection. However, antibiotics used inappropriately can be bad for you, killing harmless bacteria that may be keeping dangerous bacteria out of your intestines. Parents should learn about appropriate (and unnecessary) antibiotic use, and this includes not pressing a doctor for antibiotics when the doctor says they aren't needed.
Streptococci are everywhere. About 20% of us have them on our skin, and 10% of children have them in their throats at any given time. They don't always cause disease: that is, they don't always cause strep throat infection. However, streptococci are infectious. They are passed around in the same way as cold viruses, by coughing, sneezing, or getting mucus or saliva on the hand, then touching other people. They are less contagious than a cold virus, however.
Smoking and heavy drinking, which can damage the lining of the throat, increase the risk of bacterial infection. Frequent heartburn can also encourage throat irritation if the digestive acids rise as high as the throat. People with weak immune systems from HIV/AIDS, diabetes, cancer treatment, or corticosteroid medication use are also at higher risk.
The easiest place to catch strep throat is in a hospital. Not only are there more vulnerable people around, but hospital workers and inpatients are also more likely than average to carry GAS. Children who attend daycare, as well as daycare workers, are also at higher risk of catching bacterial infections.
Streptococcal pharyngitis, as strep throat is formally known, causes these symptoms:
Coughing, runny nose, stuffiness, and sneezing aren't associated with strep throat and are usually signs of a viral infection. It's also rare for streptococcus to invade the larynx (voice box), causing hoarseness - this is far more likely with a virus. Of course, it's possible to have both viral and bacterial infections at the same time.
It takes about 24 to 72 hours for the bacteria to incubate in the body, or become great enough in number before symptoms are seen.
Before the discovery of antibiotics, strep throat often led to serious complications. The most dangerous of these was rheumatic fever. In rheumatic fever, the immune system inflicts serious damage on the vital heart valves. This can leave a person vulnerable to heart disease later in life. Fortunately, this is a very rare occurrence today.
Other possible complications include immune overreaction in the joints (arthritis) or in the kidneys (glomerulonephritis). The bacteria can also travel up tubes that link the throat to the middle ears (the eustachian tubes). This is especially likely in young children, whose ear tubes aren't yet fully developed. This causes otitis media, which is an infection of the middle ear. The bacteria may also get into the lining of the brain and cause meningitis.
All of these complications are extremely rare, except otitis media. A few children develop a chronic pattern of recurring throat and ear infections.
The syndrome known as scarlet fever is a fairly rare, harmless complication of strep throat, and is essentially nothing more than a strep throat accompanied by a temporary red rash. The rash is most prominent on the abdomen and the sides of the chest. Some skin may peel when it subsides.
If complications do appear, they often come 1 to 6 weeks after the strep throat has passed. Call a doctor if you see any of these symptoms: