Strep Throat

Definition:

Strep throat is a bacterial infection caused by a specific type of streptococcal bacteria. Strep throat is a very common childhood illness, occurring more often in children than infants or adults. Strep throat is more common in the fall, winter and early spring seasons. Because strep throat is contagious and can possibly lead to more serious complications, identification and treatment of this bacterial infection is important.

Teaching Point: Strep throat commonly affects children of school age. Identification and treatment of this condition is important to limit spread and complications.

Causes:

As stated above, streptococcal bacteria are the cause of strep throat. A specific species of strep bacteria, known as Group A Beta Hemolytic Strep, is the culprit of the majority of strep throat infections.

Some people are known as carriers, meaning they have a reservoir of this form of bacteria in the back of their throat. Carriers are not necessarily more likely to get sick from their reservoir, but can transmit strep bacteria to others when sick.

Strep throat is contagious. It is transmitted through hand contact or nasal secretions. Contagiousness begins the day the sore throat first occurs and can be transmitted to others until up to one week after the acute phase of the illness unless antibiotics are prescribed. Most people are no longer contagious 1-3 days after taking their first antibiotic dose.

Teaching Point: Strep throat is due to streptococcal bacteria. Strep throat is contagious.

Symptoms:

Symptoms vary among children and adults. The most common ones include:

• Fever of 101.4 F or more
• Intensely sore throat
• Trouble swallowing
• White film or exudate on back of throat or on tonsils
• Body aches
• Headache
• Loss of appetite

It is often difficult to distinguish between sore throat due to strep bacteria and sore throat due to other causes, such as viruses. This difficulty is the main reason doctors will order a rapid strep test in the office setting, followed by a throat culture looking for any growth of strep bacteria. (Please see diagnosis section)

Symptoms that often accompany viral-induced sore throat that rarely accompany strep throat include:

• Cough
• Hoarse voice
• Runny nose
• Conjunctivitis (also known as "pink eye")

Another illness that is caused by a virus that often mimics strep throat is infectious mononucleosis ("mono"). Most often, mono is diagnosed in adolescents or young adults and confirmed by a blood test.

Teaching Point: Strep throat has many symptoms that overlap sore throat due to viral illness.

Risk Factors for strep throat:

There are few risk factors that increase a person's likelihood of catching strep throat. Those that are most obvious include:

• Working in or attending a child's day care center or school
• Chronic and recurrent sore throat
• Taking short, incomplete courses of antibiotics for sore throat

No underlying illness necessarily predisposes to higher likelihood of getting strep throat.

Teaching Point: The major risk factor for strep throat is close contact with a sick person in the day care or school setting.

Diagnosis:

Strep throat is not always easy to diagnose. As stated above, many viruses present with similar symptoms. Specific criteria have been developed and scientifically studied to assist medical providers in diagnosing strep throat. They are as follows:

• Temperature of 100.4 F or higher
• Absence of cough
• Tender neck lymph nodes (glands)
• Swollen tonsils with or without whitish film or exudate
• Age less than 15 years old

The presence of 4 or more of the above virtually guarantees the diagnosis of strep throat. The presence of 1 or less of the above virtually guarantees the absence of strep throat. When 2 or 3 of the above are present, testing for strep throat should occur prior to making a treatment decision.

Testing for strep throat is accomplished in one of two ways:

• Rapid strep test
• Throat culture

Rapid strep test, also known as rapid antigen detection test, identifies a specific protein of the strep bacteria. This test takes only a few minutes, is easy to perform (swabbing the back of the throat and the tonsils, if present) and is extremely accurate.

Throat culture is the best test for confirming the presence of the strep bacteria. This test takes at least 24 hours to detect strep so is a little less convenient. However, waiting 24 hours before initiating antibiotic treatment is not likely to put anyone at risk for complications related to a strep throat infection.

Additional physical exam findings can help in diagnosing strep throat. These findings are:

• Strawberry-looking tongue
• Fine, red rash on arms, legs, groin, neck and/or trunk of body

Teaching Point: Diagnosing strep throat is often based on a combination of symptoms and physical findings. Tests help confirm the presence of strep throat when there is uncertainty regarding the presence or absence of strep.

Treatments:

Antibiotics are the mainstay for treating strep throat. Penicillin is the #1 antibiotic prescribed for strep throat. Many other antibiotics are potentially useful in treating a strep throat. In people with trouble swallowing pills or liquid, injectable penicillin or other antibiotics are useful as initial therapy.

Additional treatment may include:

• Analgesics such as ibuprofen or acetaminophen
• Gargling with warm salt water
• Sucking on throat lozenges, hard candy, ice or popsicles
• Eating soft foods or drinking cool drinks

It should be noted that strep throat will go away on its own if left untreated, but usually lingers for about 10-14 days before the symptoms fully disappear.

Teaching Point: Antibiotics are the #1 treatment for curing strep throat.

Complications:

The main reason strep throat is of concern is the unlikely, but very real possibility, that complications develop as a result of a strep infection. These complications can be serious, even life-threatening. They include:

Peritonsillar abscess (collection of pus surrounding or within the tonsils). Antibiotics, combined with incision and drainage of the pus collection, is needed for getting rid of the abscess.

Rheumatic fever (symptoms include joint swelling or pains, skin lumps, skin rash, and heart murmur). This complication is extremely rare.

Kidney inflammation known medically as "glomerulonephritis". This condition will lead to bloody urine and leg swelling.

Scarlet fever often accompanies a strep throat and represents seeding of the strep bacteria in the blood. The rash of scarlet fever is usually fine, reddish, and sandpapery in texture. Antibiotics help treat scarlet fever.

Early diagnosis and treatment of strep throat has lessened the above complications over the past few decades.

Teaching Point: Strep throat has potentially serious complications. Early treatment with antibiotics can help prevent these complications.

The final word:

Most people are likely to get strep throat at one time or another. Knowing the typical symptoms and signs of strep infection will help you and your medical provider accurately diagnose this very treatable condition. Please consult your family doctor for further information.

References:

Vincent, MT, et.al. Pharyngitis. American Family Physician. 2004. 69(6).

McIsaac, WJ, et.al. The validity of a sore throat score in family practice. Canadian Medical Association Journal. 2000. 163: 811-15.

Strep Throat. American Family Physician. 2001. 63(8).

Diagnosing Strep Throat: Are There Reliable Clues? American Family Physician. 2001. 64(1).

Triage Options for Strep Throat. American Family Physician. 2005. 71(2).

Van Driel, M, et.al. Are Sore Throat Patients Who Hope for Antibiotics Actually Asking for Pain Relief? Annals of Family Medicine. 2006. November-December issue.

Group A Streptococcal pharyngitis: A practice guideline. Clinics of Infectious Disease. 1997. 25: 574-83.

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