ConditionInfections
Streptococcal Pharyngitis (Strep Throat)
Streptococcal pharyngitis, or strep throat, is a throat and tonsil infection caused by group A Streptococcus bacteria. It causes a sudden, painful sore throat, fever, pain on swallowing, swollen neck glands and often white patches on the tonsils, usually without cough or runny nose. It is most common in children aged 5 to 15. A rapid strep test or throat culture confirms it. Antibiotics such as penicillin or amoxicillin speed recovery, reduce spread and prevent complications such as rheumatic fever.
Also called: Strep throat, strep pharyngitis, group A strep throat, streptococcal tonsillitis, GAS pharyngitis
At a glance
- What it is
- A bacterial infection of the throat and tonsils by group A Streptococcus.
- Who gets it
- Mostly children 5 to 15; less common in adults and children under 3.
- Typical symptoms
- Sudden sore throat, fever, painful swallowing, swollen tender neck glands, red tonsils with white patches, no cough.
- Diagnosis
- Rapid antigen test or throat culture; symptoms alone are not reliable.
- Treatment
- Penicillin or amoxicillin for 10 days; alternatives for penicillin allergy.
- Contagious until
- At least 12 hours on antibiotics and no fever.
When to get help
Call 911 or go to the ER
- Difficulty breathing, drooling or being unable to swallow saliva
- Muffled voice, inability to open the mouth fully, and severe one-sided throat pain (possible peritonsillar abscess)
- Stiff neck, confusion, or a rapidly spreading red, painful skin area with fever
See a doctor within a day or two
- A sore throat with fever and swollen neck glands in a child, without cough or runny nose, to test for strep
- A sandpaper-like red rash with sore throat and fever (scarlet fever)
- Signs of dehydration: very little urine, dry mouth, no tears
Book a routine appointment
- Joint pain or swelling, chest pain or breathlessness 1 to 5 weeks after a sore throat (possible rheumatic fever)
- Dark or cola-colored urine or puffy eyes 1 to 3 weeks after strep (possible kidney inflammation)
- Repeated strep infections
Usually safe to manage at home
- A sore throat with cough, runny nose, hoarseness or pink eye, which suggests a virus, while you rest and drink fluids
Strep throat vs a viral sore throat
Most sore throats, especially in adults, are caused by viruses and do not need antibiotics. Clues help, but only a test can confirm strep.
| Feature | Strep throat | Viral sore throat |
|---|---|---|
| Onset | Sudden | Gradual |
| Fever | Common | Variable |
| Cough, runny nose, hoarseness | Usually absent | Common |
| Tonsils | Red, swollen, white patches | Red, sometimes patches |
| Neck glands | Swollen and tender at the front | May be swollen |
| Tiny red spots on the palate | Sometimes | Uncommon |
| Other | Headache, belly pain, vomiting in children | Pink eye, mouth ulcers |
Doctors use scoring systems (Centor or McIsaac criteria) based on fever, absence of cough, tender neck glands, tonsil swelling or exudate, and age to decide who should be tested.
Symptoms
- sudden, painful sore throat
- pain when swallowing
- fever of 38 °C (100.4 °F) or higher
- red, swollen tonsils, sometimes with white patches or streaks of pus
- tiny red spots on the roof of the mouth (petechiae)
- swollen, tender lymph nodes in the front of the neck
- headache
- stomach pain, nausea or vomiting, especially in children
- a fine, sandpaper-like rash in scarlet fever
How it spreads
Strep spreads through respiratory droplets from coughing, sneezing and talking, and through shared cups, utensils and close contact. Symptoms usually begin 2 to 5 days after exposure. Outbreaks are common in schools and daycare in late fall to spring.
Diagnosis
- rapid antigen detection test (RADT): a throat swab with results in minutes
- throat culture: a backup in children and teens when the rapid test is negative, because rapid tests can miss some cases; usually not needed in adults
- molecular (PCR) tests: highly accurate, increasingly used
Testing is generally not recommended for children under 3 without risk factors, or for people with clear viral symptoms.
Treatment
- penicillin or amoxicillin for 10 days is the standard treatment; finish the full course even when feeling better
- for penicillin allergy: cephalexin or other cephalosporins (if the allergy is not severe), azithromycin or clindamycin
- pain relief: acetaminophen (paracetamol) or ibuprofen, following the label dose; no aspirin for children or teenagers
- warm or cold fluids, soft foods, throat lozenges for older children and adults, saltwater gargles
Symptoms usually improve within 1 to 2 days of starting antibiotics. Without antibiotics, strep usually resolves in 7 to 10 days, but the risk of complications and spread is higher.
Complications
Suppurative (pus-forming)
- peritonsillar abscess
- ear infections and sinusitis
- neck abscesses
Non-suppurative (immune)
- rheumatic fever: inflammation of the heart, joints, skin and brain 1 to 5 weeks after untreated strep; can permanently damage heart valves. Antibiotics prevent it.
- post-streptococcal glomerulonephritis: kidney inflammation 1 to 3 weeks after infection, with dark urine and swelling.
- scarlet fever: a rash caused by strep toxins.
- PANDAS: a controversial association with sudden-onset OCD or tics in children.
Prevention and returning to school
- children and adults can return to school or work after at least 12 hours of antibiotics and once they are fever-free
- wash hands often; cover coughs and sneezes
- do not share cups, utensils or toothbrushes; replace the toothbrush after starting treatment
- there is no vaccine yet
Tonsillectomy may be considered for children with very frequent, documented strep infections (for example 7 or more in a year).
Frequently asked questions
What are the symptoms of strep throat?
Strep throat usually causes a sudden, painful sore throat, fever, pain swallowing, red swollen tonsils with white patches, tender swollen neck glands and sometimes headache or stomach pain. Cough and runny nose are usually absent.
How can I tell if my sore throat is strep or viral?
Strep is more likely with sudden sore throat, fever, swollen front neck glands, white patches on tonsils and no cough, especially in children 5 to 15. Cough, runny nose, hoarseness or pink eye suggest a virus. Only a strep test can confirm it.
Is strep throat contagious?
Yes, through coughs, sneezes and shared items. People are no longer considered contagious after at least 12 hours of antibiotics and once the fever is gone. Untreated, it can spread for 2 to 3 weeks.
Do you need antibiotics for strep throat?
Yes, antibiotics are recommended. They shorten symptoms, reduce spread and prevent complications such as rheumatic fever. Penicillin or amoxicillin for 10 days is the usual choice.
Can adults get strep throat?
Yes, though less often than children. About 1 in 10 adult sore throats are caused by strep. Adults who live or work with children are at higher risk.
Sources
This guide was written from current patient and clinical guidance, including:
- CDC: Strep Throat, All You Need to Know; Clinical Guidance for Group A Streptococcal Pharyngitis
- Infectious Diseases Society of America: Clinical Practice Guideline for Group A Streptococcal Pharyngitis (2012)
- American Academy of Pediatrics: Red Book, Group A Streptococcal Infections
- American Heart Association: Prevention of Rheumatic Fever and Diagnosis and Treatment of Acute Streptococcal Pharyngitis (2009)
- MedlinePlus: Strep throat