Streptococcal Pharyngitis (Strep Throat)
A bacterial throat infection caused by group A streptococcus
Quick Facts
- Type: Bacterial throat infection
- Cause: Group A streptococcus bacteria
- Key symptoms: Sudden sore throat, fever, painful swallowing
- Treatment: Antibiotics
Overview
Streptococcal pharyngitis, commonly known as strep throat, is a bacterial infection of the throat and tonsils caused by group A streptococcus. It produces a sudden, painful sore throat and is one of the few common throat infections that benefits from antibiotic treatment, since most sore throats are caused by viruses.
Strep throat is most common in school-age children but can affect people of any age. It spreads easily through respiratory droplets and close contact. While the infection itself usually clears within a few days, treatment with antibiotics speeds recovery, reduces spread, and helps prevent complications such as rheumatic fever, which can damage the heart.
Symptoms
Strep throat tends to come on quickly and often lacks the cough and runny nose typical of a cold. Common symptoms include:
- A sudden, severe sore throat
- Pain when swallowing
- Red and swollen tonsils, sometimes with white patches or streaks of pus
- Tiny red spots on the roof of the mouth
- Fever
- Swollen, tender lymph nodes in the neck
- Headache, stomach ache, or nausea, especially in children
A cough, runny nose, hoarseness, and red eyes are more typical of a viral infection and make strep less likely. A widespread fine red rash can occur with scarlet fever, a related strep illness.
Causes
Strep throat is caused by the bacterium group A Streptococcus pyogenes. It spreads from person to person through:
- Respiratory droplets: From coughing or sneezing.
- Close contact: Such as sharing utensils, cups, or food.
- Touching contaminated surfaces: Then touching the mouth or nose.
People are most contagious during the acute illness, and untreated infections can remain contagious longer. Crowded settings such as schools and households make spread more likely.
Risk Factors
- Being a child or teenager, especially ages 5 to 15
- Close contact with someone who has strep throat
- Crowded settings such as schools, daycare, or households
- Winter and early spring, when infections are more common
Diagnosis
Because strep throat looks similar to viral sore throats, testing is used to confirm the diagnosis before prescribing antibiotics.
- Rapid strep test: A quick throat swab that can detect group A strep within minutes.
- Throat culture: A swab grown in the lab, used to confirm results when the rapid test is negative but strep is still suspected, especially in children.
- Clinical assessment: Reviewing symptoms and examining the throat and lymph nodes to decide who should be tested.
Treatment
Strep throat is treated with antibiotics, along with measures to relieve symptoms.
- Antibiotics: A course of penicillin or amoxicillin is typical, with alternatives for those allergic to penicillin. It is important to finish the entire course even after feeling better, to fully clear the bacteria and prevent complications.
- Pain and fever relief: Over-the-counter acetaminophen or ibuprofen can ease throat pain and fever.
- Comfort measures: Rest, plenty of fluids, warm or cold soothing drinks, and throat lozenges for older children and adults.
People are usually no longer contagious after about 24 hours on appropriate antibiotics, once fever has resolved.
Prevention
- Wash hands often, especially after coughing or sneezing and before eating
- Cover coughs and sneezes
- Avoid sharing cups, utensils, and food with someone who is sick
- Stay home from school or work until fever-free and after at least 24 hours of antibiotics
- Replace a toothbrush after starting treatment
When to See a Doctor
See a clinician if you have a sudden severe sore throat with fever, painful swallowing, or swollen neck glands, especially without cough or runny nose, so you can be tested for strep. Seek emergency care for difficulty breathing or swallowing, drooling, a muffled voice, inability to open the mouth fully, or a stiff neck with high fever, which can signal a serious throat infection or complication.
Frequently Asked Questions
How do I know if my sore throat is strep?
Strep throat usually comes on suddenly with a severe sore throat, painful swallowing, fever, and swollen neck glands, often without a cough or runny nose. Because it can look like a viral sore throat, a rapid strep test or throat culture is needed to confirm it.
Does strep throat need antibiotics?
Yes. Unlike most sore throats, which are viral, strep throat is bacterial and is treated with antibiotics. Treatment speeds recovery, reduces spread, and helps prevent complications such as rheumatic fever. It is important to finish the full course.
How long is strep throat contagious?
Without treatment, a person can be contagious during the illness and for a while afterward. With appropriate antibiotics, people are usually no longer contagious after about 24 hours, once the fever has gone, which is when they can typically return to school or work.
What happens if strep throat is not treated?
Many cases improve on their own, but untreated strep throat can lead to complications, including abscesses around the tonsils and, in some cases, rheumatic fever, which can damage the heart. This is why testing and antibiotic treatment are recommended.
When is a sore throat an emergency?
Seek emergency care for difficulty breathing or swallowing, drooling, a muffled "hot potato" voice, inability to open the mouth, or a stiff neck with high fever. These can signal a serious throat infection that needs urgent treatment.
References
- Centers for Disease Control and Prevention (CDC). Strep Throat: All You Need to Know.
- MedlinePlus, U.S. National Library of Medicine. Strep throat.
- Mayo Clinic. Strep throat — Symptoms and causes.
- American Academy of Pediatrics (HealthyChildren.org). Strep Throat.