Sore Throat (Pharyngitis): Causes, Strep Signs and Relief

A sore throat (pharyngitis) is pain, scratchiness or irritation in the back of the throat that often gets worse when you swallow. Most sore throats are caused by viruses, such as those behind colds and flu, and get better on their own within a week. Antibiotics help only when bacteria, usually strep, are the cause, and a quick test can tell.

Key points

Viruses cause most sore throats. Cough, runny nose and hoarseness point to a virus.
Strep throat is more likely with sudden pain, fever, swollen neck glands and white patches on the tonsils, without a cough.
A rapid strep test or throat culture is the only way to know if it’s strep.
Warm drinks, honey, salt-water gargles and pain relievers ease most sore throats.
Get emergency care for trouble breathing, drooling, or being unable to swallow or open your mouth.

What causes a sore throat

Viruses

Common colds, flu, COVID-19 and other respiratory viruses cause most sore throats in adults and children. Mononucleosis (mono), caused by the Epstein-Barr virus, can cause a severe sore throat with tiredness and swollen glands that last for weeks. It is most common in teens and young adults.

Bacteria

Group A streptococcus causes strep throat. It is most common in children 5 to 15 years old and less common in adults. It spreads through coughs, sneezes and shared cups. Less often, other bacteria cause throat infections, including gonorrhea after oral sex.

Other causes

Allergies and postnasal drip (mucus dripping down the back of the throat)
Dry indoor air, especially when you breathe through your mouth at night
Acid reflux, which often causes a sore throat in the morning
Smoke, vaping and air pollution
Shouting, singing or talking a lot

Sore throat symptoms

Pain or scratchiness that is worse when swallowing or talking
Red throat and swollen tonsils
Tender, swollen glands (lymph nodes) in the neck
Hoarse or muffled voice
Fever, headache and body aches

Is it strep or a virus?

These signs make strep more likely:

Sudden throat pain and fever
White patches or streaks of pus on the tonsils
Tiny red spots on the roof of the mouth
Swollen, tender glands at the front of the neck
No cough or runny nose
In children, headache, stomach pain or vomiting
A red, sandpaper-like rash, which means scarlet fever

Cough, a runny nose, hoarseness, pink eye or mouth sores point more to a virus. Still, the two can look alike, so testing is the way to be sure.

How it’s diagnosed

A doctor will look at your throat, feel your neck and ask about other symptoms. If strep is possible, a nurse rubs a swab over the back of the throat. A rapid strep test gives results in minutes. If a child’s or teen’s rapid test is negative, the sample may be sent for a throat culture, which takes a day or two. Your doctor may also test for flu, COVID-19 or mono.

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Strep tests usually aren’t done for children under 3, because strep throat is uncommon at that age.

Treatment

Home care for any sore throat

Drink plenty of fluids. Warm tea or broth, or cold drinks and ice pops, can soothe the throat.
Stir honey into warm water or tea. Never give honey to babies under 1 year old.
Gargle with warm salt water a few times a day.
Suck on lozenges or hard candy. Don’t give these to young children, who can choke.
Use a cool-mist humidifier at night.
Rest your voice, and avoid smoke.
Take acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) for pain and fever. Never give aspirin to children or teens.
Throat sprays with a numbing medicine can give short relief.

Antibiotics for strep throat

If a test confirms strep, your doctor will prescribe an antibiotic, usually penicillin or amoxicillin. People allergic to penicillin can take another antibiotic. Take every dose, even after you feel better, to clear the infection and prevent rare problems such as rheumatic fever, which can damage the heart. Most people feel better within a day or two. You can usually go back to school or work after at least 12 hours on antibiotics and once the fever is gone.

Antibiotics don’t help viral sore throats. They can cause side effects and help germs become resistant.

Repeat strep infections

Some children get strep throat many times a year. If infections are very frequent, an ear, nose and throat doctor may suggest removing the tonsils (tonsillectomy).

Lowering your risk

Wash your hands often, especially before eating.
Don’t share cups, utensils or toothbrushes.
Cover coughs and sneezes with a tissue or your elbow.
Stay up to date on flu and COVID-19 vaccines.
Replace your toothbrush after strep throat.

When to see a doctor

A sore throat that lasts more than a week, or keeps coming back
Fever above 101°F (38.3°C), or any fever lasting more than 2 days
White patches on the tonsils, or a rash
Close contact with someone who has strep throat
Hoarseness lasting more than 2 weeks
A lump in the neck, or blood in your saliva

Get emergency care for trouble breathing, drooling or being unable to swallow saliva, trouble opening the mouth, a muffled voice with severe pain on one side, a stiff neck, or signs of dehydration such as very little urine.

Common questions about sore throats

Why does my throat hurt when I swallow?

Swallowing stretches and squeezes the inflamed lining of the throat and tonsils, so it hurts more. A virus or strep usually causes this swelling. Reflux, allergies and dry air can too. If swallowing is so painful that you can’t drink, or one side is much worse than the other, see a doctor soon.

How long does a sore throat last?

A sore throat from a cold usually improves in 3 to 5 days and is gone within a week. Strep throat gets better within a day or two of starting antibiotics. Sore throats from mono can last 1 to 2 weeks. See a doctor if yours lasts longer than a week.

Is a sore throat contagious?

The viruses and bacteria behind most sore throats are contagious. Colds and flu spread most in the first few days. Strep stays contagious until you have taken antibiotics for at least 12 hours. Sore throats from allergies, reflux or dry air are not contagious.

Why do I have a sore throat on one side?

A sore throat can feel worse on one side when one tonsil or one group of neck glands is more swollen, or when postnasal drip runs down one side. Severe one-sided pain with fever, a muffled voice and trouble opening the mouth can mean an abscess near the tonsil, which needs urgent care.