Although a painful sore throat could indicate strep throat, you may actually have another condition, like the flu or tonsillitis.

Strep throat is an infection caused by the group A Streptococcus bacterium known as Streptococcus pyogenes. Common symptoms of strep throat include:

  • a sudden sore throat
  • pain when swallowing
  • fever
  • red and swollen tonsils
  • white patches or pus on tonsils
  • small red spots on the roof of the mouth (petechiae)
  • swollen lymph nodes
  • rash (scarlet fever)
  • headache
  • stomachache
  • vomiting
  • nausea

Strep throat infections do not usually cause a cough, runny nose, hoarse voice, or pink eye (conjunctivitis), according to the Centers for Disease Control and Prevention (CDC).

Although a painful sore throat may indicate strep throat, you may actually have a viral infection. Most sore throats are the result of viruses, not group A strep bacterial infection.

If you’ve tested negative for strep throat, there are many other potential causes for your symptoms. A doctor can help make the right diagnosis and advise you on the best treatment for you.

A negative strep test may mean your symptoms are due to another infection, such as from a virus, or have a non-infectious cause. Many common viruses cause symptoms similar to strep throat.

Tonsillitis

Tonsillitis is inflammation of the tonsils. It’s a symptom of many bacterial and viral infections.

If tonsillitis is the result of bacteria, a doctor may prescribe antibiotics. For most cases of tonsillitis, medical treatment is not necessary. The inflammation should go away in 3 to 4 days.

Home treatment typically includes rest, fluids, and over-the-counter (OTC) pain medications like ibuprofen or acetaminophen.

Common cold

The common cold results from a viral infection, most often from a rhinovirus. Symptoms of the common cold include:

  • sore throat
  • runny nose
  • headaches
  • sneezing
  • coughing
  • aching muscles

You can catch a cold from respiratory droplets in the air, passed from someone else with the virus. It’s also possible to get a cold by touching a surface that has the cold virus on it and then touching your face.

Since the common cold is not a bacterial infection, antibiotics are not recommended. Home treatment, including rest, fluids, and OTC pain relievers, should help with symptoms. Most colds last about 7 to 10 days.

Influenza (flu)

The flu is a contagious respiratory condition. It’s also caused by a virus. Like the common cold, it’s spread by coming into contact with the flu virus through droplets in the air or on surfaces.

The flu can cause many of the same symptoms as the common cold. The flu might also cause:

While many people only have mild flu symptoms, in some cases the flu can be severe. Serious complications include pneumonia, ear infection, or sinus infection. Those with chronic health conditions like diabetes may have a worsening of that condition.

Many people with mild flu do not get medical treatment. A doctor may prescribe flu antiviral medications. In general, flu symptoms may last for about a week.

The CDC advises that getting vaccinated is the best way to prevent the flu.

Hand, foot, and mouth disease

This is caused by an enterovirus. Similar to the common cold and the flu, it is also spread through respiratory droplets and surface contact.

Some children with this disease do not show symptoms. Treatment is supportive. This means it involves treating the symptoms and staying hydrated.

People typically get better within 7 to 10 days.

Mononucleosis

Also called mono, this infection is usually caused by the Epstein-Barr virus. This is usually spread through bodily fluids like saliva, blood, or semen.

Treatment is supportive and involves treating the symptoms, staying hydrated, and getting plenty of rest. With home treatment, people usually feel better after 2 to 4 weeks but may continue to experience fatigue for several more weeks.

Most sore throats are caused by viruses. Some, like strep throat, are from bacterial infections. There are other, non-infectious causes of sore throat that are rarer, according to experts.

Infectious causes include:

  • rhinovirus, coronavirus, and parainfluenza viruses: lead to the common cold
  • non-group A strep bacteria: specifically groups C and G Streptococcus bacteria
  • flu viruses: specifically types A and B
  • adenovirus: can also cause conjunctivitis
  • herpes virus type 1: can also cause cold sores

Non-infectious causes include:

  • smoke irritation from cigarettes or the environment
  • acid reflux
  • allergies
  • irritation from a feeding tube while in a hospital
  • mouth inflammation from cancer treatments
  • allergic reaction to a medication, such as Stevens-Johnson syndrome

A doctor usually needs to do a test for group A Streptococcus bacterial infection in order to diagnose strep throat. This is because the symptoms of strep throat are the same as the symptoms of other infections and conditions with non-infectious causes.

The rapid test for strep can usually happen in a doctor’s office.

The doctor may also perform a throat swab culture if rapid testing is negative but there’s still a concern about strep throat or if a rapid test is not available. A throat culture involves touching the throat and tonsils with a cotton swab and sending the swab to a lab for analysis.

Your doctor will also ask about symptoms and perform a physical exam. This may include examining the inside of your mouth and throat and feeling your lymph nodes.

If left untreated, a strep throat infection can spread and cause serious conditions like:

You may want to contact a doctor if you have strep throat symptoms, especially if you do not have a cough, runny nose, hoarseness, or conjunctivitis. A doctor can usually do a rapid test in the clinic for strep throat.

If you have tested negative for strep throat and your symptoms do not improve with home treatment within 7 to 10 days, you may want to visit a doctor to investigate the cause.

If you have tested negative for strep throat, you may be experiencing a different bacterial infection or a viral infection.

Many viral infections resolve on their own in about 1 week without medical treatment.

If you have the flu, a doctor may prescribe flu antiviral medications.