Sore Throat: Is It Mono or Strep Throat?

How do you know if your sore throat is caused by mononucleosis?

Having a sore throat can be a symptom of many conditions, and many people wonder if their own sore throat might be a sign of something more serious than the common cold. Specifically, infectious mononucleosis ("mono") and infection with Streptococcus bacteria ("strep throat") are two conditions that both produce an extremely painful sore throat.

Like the common cold, infectious mononucleosis is caused by a viral infection. The virus responsible for mono is called the Epstein-Barr virus, abbreviated EBV. EBV is a very common virus worldwide, and studies show that up to 95% of the U.S. population has been infected with EBV at some point in their lives. EBV infection, especially if it occurs early in childhood, does not always cause illness, or it may cause a very mild illness that is not distinguishable from colds or other mild illnesses of childhood. However, when infection first occurs during the teen years or in young adulthood, infectious mononucleosis will develop in up to 50% of cases.

What are the symptoms of mono?

Enlargement of the spleen and inflammation of the liver may also occur. Severe complications are very rare, and the condition gradually resolves on its own. Because mono is caused by a virus and not bacteria, antibiotics are of no benefit. Therefore, treatment is directed at relieving the symptoms, which may persist for one to two months.

What are the differences between mononucleosis and strep throat?

In contrast to infectious mononucleosis, strep throat is caused by a bacterial infection. As with mono, the symptoms of strep throat can include:

Strep throat is also common in children and teens. In cases of strep throat, the tonsils are often enlarged, and red and white patches can sometimes be seen in the throat. If not treated, strep throat can lead to complications, such as rheumatic fever, later in life. Treatment involves antibiotics, and people with strep throat usually feel better after taking the antibiotics for a day or two.

Mono and strep throat account for only a small percentage of sore throats. The majority of sore throats are minor discomforts that occur in combination with other symptoms of the common cold. However, high fever, swollen lymph nodes in the neck, enlarged tonsils, and extremely painful sore throat are all warning signs that warrant a visit to the doctor to rule out mono or strep throat. Your doctor can perform simple tests in the office to determine whether your symptoms may be due to mono or strep throat.

Medically reviewed by Robert Cox, MD; American Board of Internal Medicine with subspecialty in Infectious Disease


Patient information: Infectious mononucleosis (mono) in adults and adolescents (Beyond the Basics).