Tonsillitis

• Red, swollen tonsils
• White or yellow coating or patches on the tonsils
• Sore throat
• Difficult or painful swallowing
• Fever
• Enlarged, tender glands (lymph nodes) in the neck
• A scratchy, muffled or throaty voice
• Bad breath
• Stomachache, particularly in younger children
• Stiff neck
• Headache

In young children who are unable to describe how they feel, signs of tonsillitis may include:

• Drooling due to difficult or painful swallowing
• Refusal to eat
• Unusual fussiness

Causes

Tonsillitis is most often caused by a common cold virus, but other viral and bacterial infections can also be the cause.

The most common bacterium causing tonsillitis is Streptococcus pyogenes, or group A streptococcus, the bacterium that causes most cases of strep throat.

Why do tonsils get infected?

Tonsils produce certain types of disease-fighting white blood cells. So the tonsils are believed to act as the immune system's first line of defense against bacteria and viruses that enter your mouth.

This function may make the tonsils particularly vulnerable to infection and inflammation. However, the tonsil's immune system function declines after puberty — a factor that may account for the rare cases of tonsillitis in adults.

Risk factors

Risk factors for tonsillitis include:

• Young age. Tonsillitis is most common from the preschool years to the mid-teenage years.
• Frequent exposure to germs. School-age children are in close contact with their peers and frequently exposed to viruses or bacteria that can cause tonsillitis.

Complications

Inflammation or swelling of the tonsils from frequent or ongoing (chronic) tonsillitis can cause complications such as:

• Difficulty breathing
• Disrupted breathing during sleep (obstructive sleep apnea)
• Infection that spreads deep into surrounding tissue (tonsillar cellulitis)
• Infection that results in a collection of pus behind a tonsil (tonsillar abscess)

Strep infection

If tonsillitis caused by group A streptococcus or another strain of streptococcal bacteria isn't treated or if antibiotic treatment is incomplete, your child has an increased risk of rare disorders such as:

• Rheumatic fever, an inflammatory disorder that affects the heart, joints and other tissues
• Post-streptococcal glomerulonephritis, an inflammatory disorder of the kidneys that results in inadequate removal of waste and excess fluids from blood 

Diagnosis

Your child's doctor will start with a physical exam that will include:

• Using a lighted instrument to look at your child's throat and likely his or her ears and nose, which may also be sites of infection
• Gently feeling (palpating) your child's neck to check for swollen glands (lymph nodes)
• Listening to his or her breathing with a stethoscope

Throat swab

With this simple test, the doctor rubs a sterile swab over the back of your child's throat to get a sample of secretions. The sample will be checked in a lab for streptococcal bacteria. Many clinics are equipped with a lab that can get a test result within a few minutes. However, a second more reliable test is usually sent out to a lab that can return results within 24 to 48 hours.

If the rapid, in-clinic test comes back positive, then your child almost certainly has a bacterial infection. If the test comes back negative, then your child likely has a viral infection. Your doctor will wait, however, for the more reliable, out-of-clinic lab test to determine the cause of the infection.

Complete blood cell count (CBC)

Your doctor may order a CBC with a small sample of your child's blood. The result of this test, which can often be completed in a clinic, produces a count of the different types of blood cells. The profile of what's elevated, what's normal or what's below normal can indicate whether an infection is more likely caused by a bacterial or viral agent. A CBC is not often needed to diagnose strep throat. However, if the strep throat lab test is negative, the CBC may be needed to help determine the cause of tonsillitis. 

References

http://www.webmd.com/oral-health/guide/tonsillitis-symptoms-causes-and-treatments

https://www.hse.ie/eng/health/az/T/Tonsillitis/Treating-tonsillitis.html

http://www.nhs.uk/Conditions/Tonsillitis/Pages/Symptoms.aspx

http://www.bupa.co.uk/health-information/directory/t/tonsillitis