Bacterial Pharyngitis (Strep Throat)


The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.

What is bacterial pharyngitis?

The term pharyngitis refers to inflammation of the pharynx (the part of the throat behind the mouth and nose), or of the tonsils, which are concentrations of lymphoid tissue, a type of tissue that belongs to the immune system. Bacterial pharyngitis is pharyngitis that is caused by an infection with any of a range of bacterial species. The most common category of bacteria causing pharyngitis is called Group A beta-hemolytic Streptococcus (GABHS), which is why the condition is often called “strep throat.” Still, pharyngitis also can be caused by group C and group G Streptococcus, and by several other types of bacteria, such as Fusobacterium necrophorum, Arcanobacterium haemolyticum, Neisseria gonorrhoeae, Corynebacterium diphtheria, Francisella tularensis, Treponema pallidum, Mycoplasma pneumonia, Chlamydophila pneumonia, Chlamydophila psittaci, and a mixture of various anaerobic species of bacteria (species that flourish in the absence of oxygen).

How common is bacterial pharyngitis?

About 11 million cases of bacterial pharyngitis are diagnosed each year in the United States. Most of these infections result from GABHS, which causes about 5-20 percent of pharyngitis cases in adults. Most of the remaining pharyngitis cases are from viral infections, often in connection with the common cold, but the various other bacterial groups mentioned in the last section also can cause pharyngitis, as can fungal infections.

How is bacterial pharyngitis diagnosed?

The history of your illness and the findings on the physical examination can provide your doctor with important clues, leading to a suspicion that you may have bacterial pharyngitis. The main symptoms raising suspicion are fever, chills, and fatigue, along with a sore throat, especially when you swallow. On physical examination, the key finding is the swollen, red, tonsils, often with spots of white pus. Based on the presence or lack of certain other symptoms, your age, factors in your medical history, and whether the spots are visible in your throat, your doctor will go through whats called the modified Centor score to calculate a score that estimates the probability that you have a GABHS infection. Next, the doctor will swab your throat to perform whats called a rapid Streptococcal antigen test. This may be enough to diagnose you, but if any uncertainty remains, the doctor may order a throat culture from swabbed samples. In this test, the sample from your throat is swept onto a special plate that is put into an incubator and reveals within 24-48 hours, whether you have a GABHS infection. These tests are very important because viral pharyngitis can look the same as bacterial pharyngitis, but treatment is different for the two conditions.

Does bacterial pharyngitis cause problems during pregnancy?

Bacterial pharyngitis causes sore throat, painful swallowing, and fever, and makes you very tired. The fever, in turn, can lead to, or worsen, dehydration. Complications can develop, including acute rheumatic fever, which in turn can lead to problems in your heart valves; kidney problems (acute post-streptococcal glomerulonephritis), arthritis, spreading of the infection to cause abscesses and other infections in body parts near the throat as well as throughout the body (sepsis), toxic shock syndrome, and Lemierre syndrome (infectious clotting in the jugular vein in the neck). The risk for developing most of these complications disappears or decreases significantly when the bacterial pharyngitis is diagnosed early and treated with antibiotic therapy. To prevent acute rheumatic fever, for instance, antibiotic treatment must begin within nine days of the infection.

Does bacterial pharyngitis during pregnancy cause problems for the baby?

Bacterial pharyngitis may cause problems for the developing baby indirectly because of the fever. Some studies have suggested that fever during pregnancy can increase a babys risk of having congenital defects involving the heart and other organs. Also, a recent study identified maternal fever as a possible risk for the baby developing autism spectrum disorder. There is also some concern about the possibility that a baby can develop a severe heart malformation resulting from the mothers immune system responding to a GABHS infection with antibodies that cross through the placenta.

What to consider about taking medications when you are pregnant or breastfeeding:

  • The risks to yourself and your baby if you do not treat the bacterial pharyngitis
  • The risks and benefits of each medication you use when you are pregnant
  • The risks and benefits of each medication you use when you are breastfeeding

What should I know about using medication to treat bacterial pharyngitis during pregnancy?

The US Centers for Disease Control and Prevention (CDC) recommends that streptococcal pharyngeal diagnosis be confirmed with laboratory testing prior to the initiation of antibiotic treatment in almost all patients. The reason is that most cases of pharyngitis are viral, particularly in adults. Antibiotics are not effective against viral infections, and misusing such drugs encourages the spread of resistance to antibiotics through strains of bacteria that are not resistant yet.

The gold standard treatment for confirmed cases of bacterial pharyngitis is antibiotic medication. This can consist of any of a few available forms of penicillin (such as amoxicillin or penicillin V), macrolides (such as azithromycin or clarithromycin), cephalosporins (such as cephalexin or cefadroxil), or clindamycin. Most of the available drug regimens, such as amoxicillin and clindamycin, are considered safe during pregnancy.

The other main category of medications used in those with bacterial pharyngitis are medications against fever and pain. There are three main categories of such drugs. One group consists of acetaminophen in the United States and paracetamol in several other countries. Another group is called non-steroidal anti-inflammatory drugs (NSAIDs), which include ibuprofen, naproxen, and many others. Along with being antipyretic (reducing fever), NSAIDs also reduce inflammation. The third group, called salicylates, includes aspirin, which technically is also a kind of NSAID because it reduces inflammation. There is concern that NSAIDs and salicylates may be harmful to the developing baby, but acetaminophen and paracetamol are thought to be safe.

Who should NOT stop taking medication for bacterial pharyngitis during pregnancy?

Your doctor can switch you from one antibiotic to another if there are problems with side effects. Most pregnant women who need acetaminophen or paracetamol to eliminate fever during pregnancy should not stop taking the
drug because there is concern that fever could be harmful to the developing baby. The exception is women who have liver problems, but having liver problems in the first place already makes a successful pregnancy very challenging.

What should I know about choosing a medication for my bacterial pharyngitis during pregnancy?

The major issue affecting the choice of medication is whether you have an allergy to a particular class of antibiotics, such as penicillins.

You may find Pregistrys expert reports about the individual medications to treat bacterial pharyngitis here. Additional information can also be found in the sources listed at the end of this report.

What should I know about taking a medication for my bacterial pharyngitis when I am breastfeeding?

There are many different antibiotic drugs. Some are a concern during breastfeeding while others are not, depending on whether they have been found to enter breastmilk, and if so, whether they enter breastmilk in significant quantities to do harm. Bacterial pharyngitis is a serious infection that can lead to life-threatening complications. Thus, avoiding antibiotics is not an option, but particular drugs can be selected with minimal passage into breastmilk.

What alternative therapies besides medications can I use to treat my bacterial pharyngitis during pregnancy?

There are no viable alternatives to antibiotic and anti-fever medication, as fever during pregnancy can lead to problems for the baby (see above), and a GABHS infection that goes untreated can lead to severe, short-term, and long-term complications, including trouble with your heart valves.

What can I do for myself and my baby when I have bacterial pharyngitis during pregnancy?

Do not delay in seeing your doctor to get a rapid Streptococcal antigen test or a culture, so that antibiotic treatment can begin immediately to prevent complications.

Resources for bacterial pharyngitis in pregnancy:

For more information about bacterial pharyngitis during and after pregnancy, contact (800-994-9662 [TDD: 888-220-5446]) or check the following links:

  • Mayo Clinic: Sore Throat
  • Pharyngitis During Pregnancy


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Last Updated: 07-01-2020
General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.

Medications for Bacterial Pharyngitis (Strep Throat)

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