About strep throat

Creative Commons image by Nathan McCurley

Strep throat is a bacterial infection of the throat and tonsils caused by Streptococcus pyogenes. Although people of all ages can be affected, it most commonly occurs in school-aged children and teenagers.

Strep throat spreads quickly in schools, day care centres, and other areas where children are in close proximity for several hours a day.


Strep throat is less common than many people believe. Most self-diagnosed cases of "strep throat" are actually viral tonsillitis. Viral tonsillitis resolves on its own, without the need for antibiotics. Strep throat must be treated with antibiotics; untreated strep throat can cause serious, long-term health problems such as heart valve damage.


An accurate diagnosis of strep throat is important. Treating everyone who has a sore throat with antibiotics contributes to antibiotic resistance in bacteria. On the other hand, failing to treat a genuine case of strep throat can be dangerous. Physicians use two tests to determine whether a patient has strep throat or a viral infection. A swab is used to collect cells for testing from the patient's throat. The first test performed is usually a rapid strep test; results are available in about 15 minutes. A positive result is considered accurate and no further testing is necessary. However, false negatives are fairly common, so if the result is negative the sample is sent to a laboratory to be cultured. Cultures for Streptococcus pyogenes are very accurate and take only 24 to 48 hours; the bacteria produce a telltale clear halo when cultured on blood agar.


Strep throat infection becomes symptomatic one to three days after the person is exposed to the infection. The most prominent symptoms are throat pain and fever. On examination, the throat is typically red with white or yellow patches, especially on the tonsils. Difficulty swallowing may occur due to swelling and irritation in the throat. Lymph nodes on the sides of the neck may be swollen. Some people with strep throat experience other symptoms, including headache, stomach pain, loss of appetite and skin rash.


Left untreated, or inadequately treated, strep throat can cause serious complications. Skin is sometimes infected, leading to redness, pain, and swelling. Scarlet fever and toxic shock syndrome can result from untreated strep throat; these conditions are caused by the same bacteria that cause strep throat. Rheumatic fever is an autoimmune disease of the heart; it is usually caused by untreated strep throat and may go undetected until years later. Rheumatic fever is a chronic, incurable disease that can cause inflammation and scarring of the heart valves. Prompt treatment of strep throat with antibiotics can prevent these complications.


Treatment for strep throat usually consists of antibiotics, rest, and over the counter pain relievers to reduce swelling and discomfort. Symptoms usually improve within two to three days of beginning antibiotics, but it is extremely important to take the entire course. Stopping antibiotics early can lead to the same complications that leaving it untreated can. If you are affected by strep throat, keep in mind that it is highly contagious and can be spread to others by sharing food, towels, or drinking glasses while ill. Always cover your mouth when sneezing or coughing, and be sure to wash your hands frequently, especially after blowing your nose.