When does my child needs a strep test?
All children, at some point or another, will experience a sore throat. Many parents worry that their child’s sore throat is caused by the bacteria Streptococcus (strep throat) and will require antibiotics. However, only 10-20% of children with a sore throat actually have strep. If your child does not have strep, their sore throat does not require antibiotics. Their sore throat is likely caused by a virus and is most likely the start of the common cold. For more information on the common cold and other symptoms your child may experience besides a sore throat, click here.
What is strep throat?
Strep throat is a bacterial infection of the back of the throat and tonsils. The bacterium is called Group A strep or Streptococcus pyogenes. It causes a bad sore throat, fever, swelling and redness of the tonsils, as well as enlarged tender lymph nodes in the neck (commonly known as swollen glands). Many patients will also experience headaches and/or stomach aches. Some kids will even throw up. Strep throat plus a fine, red rash that feels like sandpaper is called scarlet fever.
Who gets strep and how?
Strep throat is most common in school aged children between the ages of 5 and 15 years and is spread through droplets from the respiratory tract, otherwise known as saliva. That means when an infected person coughs or sneezes, little droplets with bacteria are released from the respiratory tract and settle onto desks, pencils and doorknobs (to name a few). Anyone who touches these items and then touches their mouth or face can get sick. Sharing cups or utensils with an infected person can also give you the bacteria and make you sick. Strep has an incubation period of 2-5 days which means it may take up to 5 days after exposure to experience any symptoms.
How is strep treated?
The first thing you should know is why strep is treated. Not only does treatment reduce the length of symptoms and help prevent spread, but treatment also prevents future complications from kidney disease (post-strep glomerulonephritis) and rheumatic fever. Rheumatic fever can cause a whole bunch of symptoms but most notably are fever, joint pain and swelling, nodules under the skin, a heart murmur, a rash and jerky movements called Sydenham chorea. Permanent damage to the valves in the heart can occur so it’s very important to treat your child’s strep as directed by your doctor.
Antibiotics are necessary to treat a strep throat infection, however in order to avoid over use of antibiotics and contribute to antibiotic resistance, do not request these medications for sore throats that are not due to strep. The first line treatment for strep is penicillin or amoxicillin. Your doctor may also prescribe a first generation cephalosporin like Keflex or if you are allergic to these medications your doctor may prescribe azithromycin. Once your child is on antibiotics for 24 hours they can safely return to school without spreading their infection. Make sure to take all antibiotics as prescribed and discard any leftovers.
So how do we decide who gets a strep test?
I will admit that I test way more kids for strep than I think clinically have strep. I mostly do this to ease a parent’s fear that their child might have strep, especially when it is going around their school. However, if I was really using the correct guidelines, known as the Centor criteria, most kids would not be getting them done. In fact, over testing can pick up children who are carriers of the bacteria so they are inappropriately treated for an infection that they don’t have. Here is how the criteria work:
Each item below gets 1 point for a patient presenting with a sore throat
- Absence of cough
- Swollen and tender lymph nodes
- Temperature >100.4
- Tonsillar exudate or swelling (I frequently see redness, inflammation and palatal petechiae more than white spots)
- 3-14 years old (subtract 1 point if over 45 years old)
Patients who score 2-4 qualify for strep testing, although you do have the option to test a patient with a 1. Patients with a score of 1 are at fairly low risk of actually having strep. For children under 3 years old, they are not only unlikely to have strep but they do not routinely get rheumatic fever following an infection with strep, therefore the recommendation is not to test. However, if your doctor is looking for a cause of an illness and the child was exposed, testing is not out of the question. Patients who score a 5 can technically be treated empirically with antibiotics based on guidelines, but I always do a test to be sure. The 2 tests available are the rapid antigen test (in-office) and a culture (grown in a laboratory) to look for bacteria. Many doctors will send a culture on clinically relevant patients if the rapid testing is negative for strep or if the patient presents with less than 48 hours of symptoms. If the rapid testing is positive, your doctor will order antibiotics.
So the take home message is this, if your child has a sore throat, give him or her some pain reliever for 1-2 days. If it persists without any cold symptoms, especially if there is a fever, go see your doctor for a strep test. Of course, for any questions regarding your child’s health, call your pediatrician.