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What
is group A streptococcus (group A strep)?
Group A
streptococcus (group A strep) is a bacterium that is commonly found in
the throat and on the skin. The letter "A" refers to a
classification of bacteria in the genus Streptococcus according
to the makeup of the organism's cell wall. Group A strep bacteria
might cause no symptoms of disease, but they can also cause infections
that range from mild to life-threatening.
Where
is group A strep found?
Group A strep
bacteria are found worldwide.
How
do people get group A strep infections?
Group A strep
bacteria are spread by direct person-to-person contact. The bacteria
are carried in discharges from the nose or throat of an infected
person and in infected wounds or sores on the skin. The bacteria are
usually spread when infected secretions come in contact with the
mouth, nose, or eyes of an uninfected person. They can also enter the
body through a cut or scrape.
The risk of
spreading the infection is highest when an infected person is ill or
has an infected wound. Infected persons who have no symptoms are much
less contagious. Household objects like plates, cups, and toys do not
play a major role in the spread of group A strep.
What
kinds of illnesses does group A strep cause?
Group A strep
usually causes relatively mild illnesses, such as streptococcal sore
throat (strep throat) and streptococcal skin infections (impetigo).
Group A strep can also cause more serious illnesses such as scarlet
fever, rheumatic fever, postpartum fever, wound infections, and
pneumonia.
Occasionally, a
deadly type of group A strep bacteria can invade the blood, muscle and
fat tissue, or lungs and cause a serious and often life-threatening
type of infection called invasive group A strep. Two rare, but very
severe, forms of invasive group A strep infections are necrotizing
fasciitis and streptococcal toxic shock syndrome.
Necrotizing
fasciitis (sometimes referred to as "the flesh-eating
disease") is an infection that attacks the deep layers of tissue
(fascia). It is usually caused when a deadly strain of group A strep
infects an opening in the skin. For unknown reasons, the strain
becomes very aggressive and releases a toxin (poison) that quickly and
irreparably destroys flesh and muscle. Doctors often must remove skin,
large groups of muscle, or entire limbs to save a person's life.
Streptococcal
toxic shock syndrome, another type of rapidly progressing strep
infection, causes a dangerous drop in blood pressure, shock, and
damage to the kidneys, liver, and lungs. As in necrotizing fasciitis,
the toxin damages the tissues and organs so quickly that treatment is
difficult and often too late.
What
are the signs and symptoms of group A strep infection?
Signs and
symptoms depend on the type of illness caused by group A strep. Strep
throat causes fever, sore throat, and swollen lymph glands. Strep skin
infection causes red, weeping skin sores. Scarlet fever causes all the
symptoms of strep throat plus a characteristic rash on the neck,
chest, skin folds, and inner thighs. The rash can often be felt easier
than seen.
Early signs and
symptoms of necrotizing fasciitis are fever and severe pain, swelling,
heat, and redness at a wound site. Necrotizing fasciitis is known for
the speed with which it attacks and destroys muscle and flesh.
Early signs and
symptoms of streptococcal toxic shock syndrome often include fever,
dizziness, and confusion. Streptococcal toxic shock syndrome has no
sign or symptom that distinguishes it from other illnesses.
How
soon after exposure do symptoms appear?
Symptoms appear
quickly, usually within 1 to 3 days.
How
is group A strep infection diagnosed?
The infection is
diagnosed by culture of the organism in a laboratory. Strep throat can
also be diagnosed by a rapid strep test.
Who
is at risk for group A strep infections?
Anyone can become
infected with group A strep. However, people with long-term illnesses
like cancer, diabetes, and kidney disease, and those who use
medications such as steroids, are at higher risk for invasive disease.
Breaks in the skin, like cuts, surgical wounds, or chickenpox
blisters, can also provide an opportunity for the bacteria to enter
the body.
What
is the treatment for group A strep infection?
Group A strep
infections can be treated with many different antibiotics. Early
treatment can reduce the risk of death from invasive disease, but it
does not prevent death in every case.
How
can group A strep infections be prevented?
- Wash
hands thoroughly and often with soap and warm water, especially
after coughing and sneezing, before preparing foods, and before
eating.
- Anyone
with a sore throat with fever should see a health-care provider to
get a throat culture or rapid test to detect strep infection.
Persons with strep throat should stay home from work, school, or
day care until 24 hours after taking an antibiotic.
Keep
all wounds clean, and watch for possible signs of infection: rapidly
increasing redness, swelling, drainage, and pain at the wound site.
Anyone with signs of an infected wound, especially if fever develops,
should seek medical care right away.
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