Strep throat is a contagious infection caused by the bacterium Streptococcus pyogenes.
Strep throat primarily affects children, especially those between the ages of five and 15. Adults whose immune systems have been weakened by stress or other infections are also at risk. Most sore throats are associated with viral infections such as the common cold or the flu. Strep throat is responsible in only about 10%–15% of cases. Many people carry Streptococcus pyogenes in their systems without even knowing it. It can survive in the lining of the throat or nose for years without producing symptoms. Almost 20% of people in general good health may be harboring this bacterium unsuspectingly, according to one statistic.
Strep throat is often mistaken for a cold or the flu. It is important, however, to identify strep throat because if left untreated it can lead to serious health problems. In rare cases, untreated strep throat may increase the risk of developing scarlet or rheumatic fever. Rheumatic fever, in turn, is associated with meningitis and diseases affecting the heart, skin, kidneys, and joints. Strep throat may return repeatedly if not treated effectively the first time.
Another reason for getting treatment for strep throat is that Streptococcus pyogenes belongs to a group of diseasecausing bacteria that produce superantigens. Superantigens are a group of toxins that have the ability to trigger excessive and abnormal activation of the body's T cells. T cells are produced in the thymus gland and regulate the human immune system's response to infection. Superantigens are being studied intensively for their roles in causing disease. Streptococcus pyogenes and Staphylococcus aureus together produce 19 different superantigens.
Causes & symptoms
Most people develop strep throat through close contact with someone who has an untreated strep infection. Infected mucus from the nose or throat is often spread via sneezing or coughing. Carriers of Streptococcus pyogenes who do not show symptoms of strep throat are less likely to infect others, as are people with strep throat who have received antibiotic therapy for 24 hours or more. Strep throat is not usually transmitted through casual contact. In rare cases, strep can develop after exposure to infected food, dairy products, or water.
People with weakened immune systems are more likely to become infected with strep throat. This infection can occur when the body is battling a cold or the flu. Stress or physical exhaustion can also weaken the immune system and increase the risk of bacterial infection. Strep throat usually strikes during the winter months. Symptoms develop two to four days after being infected.
While cold or flu symptoms often develop gradually over a period of several days, the symptoms associated with strep throat occur with little warning. Classic symptoms of strep include sore throat and fever. Other tell-tale signs may include swollen and tender lymph glands in the neck, redness on the inside of the throat, inflamed tonsils or gray/white patches on the tonsils, and headache. Trouble swallowing can also occur, and red specks may be visible on the roof of the mouth. Nausea and stomach pain are more likely in children infected with strep. Unlike a cold or the flu, strep throat does not usually produce cough or a stuffy, runny nose.
Most doctors who suspect strep throat recommend a rapid strep test to confirm the diagnosis. This painless
test involves using a swab to remove a specimen from the throat of the infected person. The results of the test are available in 10–20 minutes. In addition, the doctor may send a similar specimen to a laboratory to have a throat culture performed, which takes a day or two to complete. A negative strep test or culture usually indicates that the cause is viral in nature, in which case antibiotics are of no help.
Conventional medicine is very successful in treating strep throat. However, several alternative therapies may help to resolve the disease or relieve symptoms. Herbal remedies such as echinacea (Echinacea spp.), goldenseal (Hydrastis canadensis), and garlic (Allium sativum) are believed to strengthen the immune system and combat bacterial infections.
One of its active agents is a chemical called berberine. This alkaloid is believed to have antibiotic effects against streptococci bacteria. It may also help to prevent Streptococcus pyogenes from attaching itself to the throat lining, according to a study published in the journal Antimicrobial Agents and Chemotherapy in 1988. Goldenseal is also believed to increase the activity of disease-fighting white blood cells.
This popular herb fights viral and bacterial infections by boosting the immune system, according to herbalists. Echinacea may also combat strep throat by interfering with the production of hyaluronidase, an enzyme that helps the offending bacterium to grow and spread.
The focus of hundreds of medical studies and papers, garlic is believed to be an antibiotic as well as an antiviral. As an added benefit, garlic may also prevent atherosclerosis, lower cholesterol levels, and act as an antioxidant.
Zinc and ginger (Zingiber officinale) are sometimes recommended to help treat symptoms of sore throat. In addition to strengthening the immune system, zinc may reduce throat inflammation and pain regardless of the cause. Ginger may have analgesic properties and ease throat irritation.
In the practice of homeopathy, belladonna, lachesis, and mercurius are usually the remedies of choice for strep throat and other causes of throat irritation. Which remedy to use depends on the exact nature of the symptoms. These homeopathic treatments are not recommended for more than a few days or symptoms may actually return.
Vitamin C may also help to boost the immune system. In some studies, it has been shown to shorten the duration of colds.
Antibiotics, the conventional treatment of choice, are very effective in curing strep throat. They also ease symptoms and are generally believed to reduce the risk of serious complications such as rheumatic fever. Ten days of oral penicillin is a typical course of therapy. People allergic to this drug usually take erythromycin instead. In some cases, a single injection of antibiotics may be preferred. It is important to complete the full course of antibiotic therapy (even if symptoms begin to subside earlier) in order to resolve the disease and prevent the development of complications. To further alleviate symptoms, acetaminophen or ibuprofen may also be used.
Studies of bacterial resistance to various drugs indicate that the strains of S. pyogenes found most commonly in the United States have developed some resistance to erythromycin as of 2002. As a result, doctors are more likely to prescribe antibiotics that belong to a newer group of drugs called quinolones. It is important to take quinolone antibiotics exactly as directed, as they have a number of side effects.
The symptoms associated with strep throat usually begin to disappear within several days even without treatment. When antibiotics are used, fever may subside within 24 hours, and the course of the illness may be shortened by two days.
People who use alternative remedies in the absence of antibiotics should consult a doctor if symptoms do not subside within a week. In these cases, the use of antibiotics is strongly recommended.
Washing the hands frequently can help to prevent strep throat. Exposure to infected people should also be avoided. In order to prevent transmission of the disease within households, consult a doctor if any family member suddenly develops a sore throat (especially if it is accompanied by fever).
Boosting the immune system is also important to help prevent the development of strep throat. Vitamin C and zinc are often recommended for this purpose, as are goldenseal, echinacea, and garlic. Reducing stress and getting proper sleep can also strengthen the body's defenses against infection.
Bennett, Claude J., and Fred Plum. Cecil Textbook of Medicine. Philadelphia, PA: W.B. Saunders Company, 1996.
Murray, Michael T., and Joseph Pizzorno. Encyclopedia of Natural Medicine. Rocklin, CA: Prima Publishing, 1998.
Barros, M.G. "Soothing Sore Throats Gingerly." Cortlandt Forum 67 (1995): 86-16.
Critchley, I. A., D. F. Sahm, C. Thornsberry et al. "Antimicrobial Susceptibilities of Streptococcus pyogenes Isolated from Respiratory and Skin and Soft Tissue Infections: United States LIBRA Surveillance Data from 1999." Diagnostic Microbiology and Infectious Disease 42 (February 2002): 129-135.
Llewelyn, M., and J. Cohen. "Superantigens: Microbial Agents That Corrupt Immunity." Lancet Infectious Diseases 2 (March 2002): 156-162.
Sun, D., H.S. Courtney, and E.H Beachey. "Berberine sulfate blocks adherence of Streptococcus pyogenes to epithelial cells, fibronectin, and hexadecane." Antimicrob Agents Chemother 32, no. 9 (1988): 1370-4.
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National Institute of Allergy and Infectious Disease. http://www.niaid.nih.gov.
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