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What's the difference between tonsillitis and strep throat?

Medically reviewed by Carmen Pope, BPharm. Last updated on Aug 21, 2023.

Official answer


The main difference between tonsillitis and strep throat is that tonsillitis is a condition caused by bacteria or viruses that causes inflammation of the tonsils, whereas strep throat is a certain type of tonsillitis caused by group A Streptococcus bacterium.

Tonsillitis may also be called a sore throat because that is the main symptom.

What is tonsillitis?

Our tonsils are two oval-shaped clusters of lymph cells that sit at the back of our throat. Although they seem large in children, they tend to get smaller as people age. They are part of our immune system and are the first line of defense against bacteria and viruses entering our throat. They also help prevent foreign objects from slipping into the lungs and produce white blood cells and antibodies.

Even though our tonsils help protect us from bacteria and viruses, they are also vulnerable to infection. When our tonsils are infected the condition is called tonsillitis.

Symptoms of tonsillitis include:

  • Swollen and red-looking tonsils
  • A sore throat
  • Difficulty swallowing
  • A fever
  • Swollen and tender lymph nodes in the neck.

Other symptoms may include:

  • A hoarse-sounding voice
  • Bad breath
  • Difficulty swallowing or very painful swallowing
  • Earaches
  • Headaches
  • Stomach aches
  • White or yellow spots on the tonsils.

Young children may also be irritable, have a poor appetite and drool a lot. Tonsillitis is common and most often diagnosed in children from preschool age to mid teens, although it can occur at any age.

It is contagious and viruses are the most common cause, although 30 to 40% of tonsillitis cases are caused by bacteria, such as group A streptococcal bacteria (tonsillitis caused by this type of bacteria is called Strep throat). Tonsillitis caused by Strep throat can lead to serious complications if left untreated.

Most cases of tonsillitis resolve by themselves within 7 to 10 days without any treatment. In more severe cases, antibiotics or surgery might be required.

What is Strep throat?

Sore throats caused by Streptococcus pyrogenes bacteria, a type of Group A streptococci, are referred to as Strep throats.

Symptoms of a Strep throat tend to come on quickly and are more likely to affect children rather than adults. They tend to be very painful and symptoms persist for a lot longer than sore throats caused by other microbes. Swallowing may be particularly difficult. Other symptoms that are more likely to occur with a Strep throat include:

  • Very red and swollen-looking throat and tonsils; sometimes streaks of pus or red spots on the roof of the mouth are visible
  • Headache
  • Fever and Chills
  • Swollen and tender glands (lymph nodes) in the neck
  • Vomiting or nausea (mostly in children.

Some people are susceptible to the toxins (poisons) produced by the S. pyrogenes bacteria, and develop a bright red rash that feels like sandpaper to the touch. A rash caused by S. pyrogenes bacteria is known as Scarlet Fever (also called scarlatina).

Untreated, as many as one in ten children with Strep throat will develop Scarlet Fever, although the incidence is markedly reduced with timely antibiotic use. Most cases occur in children between the ages of five and fifteen, particularly those exposed to other people with scarlet fever.

The rash typically starts on the neck, underarm or groin as small, flat red blotches that gradually become fine bumps and feel rough to the touch. In the body folds (such as in the armpits, elbows, and groin) the rash may appear a brighter red (called Pastia's lines). Facial flushing is common although a pale area may remain around the mouth. After seven days, the rash fades and some skin peeling may occur over the next month or longer, particularly around the fingertips, toes and groin area.

Rheumatic fever can develop following a Strep throat infection or scarlet fever. Although rare in the contiguous U.S., the disease is still prevalent in children of Samoan descent living in Hawaii and residents of American Samoa.

Symptoms of rheumatic fever usually manifest 14 to 28 days after an S. pyrogenes infection. Because the bacteria trick the body's immune system into attacking healthy tissues, the disease can affect the heart, joints, skin, and the brain. Symptoms of rheumatic fever include:

  • Fever
  • Abdominal pain
  • Chest pain or shortness of breath
  • Joint swelling, pain, redness, or warmth
  • Nose bleeds
  • A rash on the upper part of the arms or legs (usually ring-shaped or snake-like)
  • Skin nodules or lumps
  • Unusual crying or laughing or quick jerky movements of the face, hands, or feet.

Rheumatic fever has the potential to cause life-long cardiac problems if not treated promptly or properly. Antibiotics are effective at preventing the disease if administered within nine days of symptoms. Children who develop rheumatic fever may need regular penicillin injections until the age of 21 or for 10 years after diagnosis.

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