Strep Throat

Streptococcal sore throat, or strep throat as it is more commonly called, is an infection caused by group A Streptococcus bacteria. The main target of the infection is the mucous membranes lining the pharynx. Sometimes the tonsils are also infected (tonsillitis). If left untreated, the infection can develop into rheumatic fever or other serious conditions.

Strep throat is a common malady, accounting for 5–10% of all sore throats. Strep throat is most common in school age children. Children under age two are less likely to get the disease. Adults who smoke, are fatigued, or who live in damp, crowded conditions also develop the disease at higher rates than the general population.

The malady is seasonal. Strep throat occurs most frequently from November to April. In these winter months, the disease passes directly from person to person by coughing, sneezing, and close contact. Very occasionally the disease is passed through food, most often when a food handler infected with strep throat accidentally contaminates food by coughing or sneezing.

Once infected with the Streptococcus, a painful sore throat develops from one to five days later. The sore throat can be accompanied by fatigue, a fever, chills, headache, muscle aches, swollen lymph glands, and nausea. Young children may complain of abdominal pain. The tonsils look swollen and are bright red with white or yellow patches of pus on them. Sometimes the roof of the mouth is red or has small red spots. Often a person with strep throat has a characteristic odor to their breath.

Others who are infected may display few symptoms. Still others may develop a fine, rough, sunburn-like rash over the face and upper body, and have a fever of 101–104ºF (38–40ºC). The tongue becomes bright red with a flecked, strawberry-like appearance. When a rash develops, this form of strep throat is called scarlet fever. The rash is a reaction to toxins released by the streptococcus bacteria. Scarlet fever is essentially treated the same way. The rash disappears in about five days. One to three weeks later, patches of skin may peel off, as might occur with a sunburn.

Strep throat can be self-limiting. Symptoms often subside in four or five days. However, in some cases untreated strep throat can cause rheumatic fever. This is a serious illness, although it occurs rarely. The most recent outbreak appeared in the United States in the mid-1980s. Rheumatic fever occurs most often in children between the ages of five and 15, and may have a genetic component, because susceptibility seems to run in families. Although the strep throat that causes rheumatic fever is contagious, rheumatic fever itself is not.

Rheumatic fever begins one to six weeks after an untreated streptococcal infection. The joints, especially the wrists, elbows, knees, and ankles become red, sore, and swollen. The infected person develops a high fever, and possibly a rapid heartbeat when lying down, paleness, shortness of breath, and fluid retention. A red rash over the trunk may come and go for weeks or months. An acute attack of rheumatic fever lasts about three months. Rheumatic fever can cause permanent damage to the heart and heart valves. It can be prevented by promptly treating streptococcal infections with antibiotics. It does not occur if all the Streptococcus bacteria are killed within the first 10–12 days after infection.

In the 1990s, outbreaks of a virulent strain of group A Streptococcus were reported to cause a toxic-shock-like illness and a severe invasive infection called necrotizing fasciitis, which destroys skin and muscle tissue. Although these diseases are caused by group A Streptococcus, they rarely begin with strep throat. Usually the Streptococcus bacteria enter the body through a skin wound. These complications are rare. However, since the death rate in necrotizing fasciitis is 30–50%, prompt medical attention for any streptococcal infection is prudent.

The Streptococcus bacteria are susceptible to antibiotics such as penicillin. However, in some 10% of infections, penicillin is ineffective. Then, other antibiotics are used, including amoxicillin, clindamycin, or a cephalosporin.

See also Bacteria and bacterial infection; Streptococci and streptococcal infections