What is it?
Tonsillitis is an inflammation of the tonsils. It is most commonly caused by a viral or bacterial infection – when it’s caused by a bacterium called group A streptococcus, the condition is sometimes referred to as strep throat.
The most noticeable symptom is often pain in the throat, which gets very bad when swallowing. Other signs include red and swollen tonsils, fever, and a general sense of feeling ill.
Tonsillitis is most common in children. The prevalence of chronic tonsillitis, meaning that the person has suffered from several episodes during a relatively short space of time, is in the USA about 0.7% of people. Cases with only one or a couple of episodes are much more common than that. In 40% of people, symptoms will resolve within 3 days, and in 85% of people, they will resolve within a week.
What causes it?
Tonsillitis can be caused by a number of different viruses and bacteria. While the tonsillitis itself doesn’t “spread”, the infectious agents that cause it do. Because they infect the respiratory tract, they are contained in the droplets that we spread to our surroundings when we cough or sneeze. If one of these droplets manages to make it to our tonsils, which normally participate in fighting infections, the microbes might get a grip of our immune system and cause an inflammation which mostly causes the symptoms of tonsillitis.
What happens during it?
Since there are many different microbes that can cause tonsillitis, there are also many different ways in which the symptoms can come about. A common factor is, however, that an inflammation starts in the tonsils.
Our body has many defense mechanisms against pathogens, and inflammation is one of them. When cells notice that there’s something wrong in a certain area of the body, they start to produce inflammatory mediators. These molecules cause the symptoms of inflammation – blood vessels become bigger and more permeable in the area to direct as many white cells as possible to fight the infection, for example. This is why the inflamed area becomes red and swollen. The molecules can also irritate the pain receptors of neurons and that way send signals to the brain which will be interpreted as pain. If microbes have made it into the tonsil tissue, an inflammation starts there.
It is thought that the bacterium that causes strep throat, for example, manages to hide from the body’s immune system by invading epithelial cells (cells in the inner and outer surfaces of the body). This would explain why antibiotics are rarely that effective – they aren’t taken inside the cells in sufficient amounts. They also carry a protein on their surface, which prevents immune cells from “ingesting” and that way destroying them, as would normally happen.
How can it be treated?
As most cases resolve without specific treatment, taking care of someone with tonsillitis usually focuses on relieving the symptoms. It’s important that the person gets enough to drink and eat, even if swallowing is very painful. Painkillers might be useful for the sore throat.
Even if the tonsillitis has been confirmed to be caused by a bacterium, antibiotics aren’t necessarily prescribed. This is because they often aren’t able to speed up recovery but only cause side effects, and the use of unnecessary antibiotics should be discouraged in order to avoid antibiotic resistance. In particularly severe cases, or those that don’t seem to get better, they can be used.
If a person suffers from recurrent episodes of disabling tonsillitis, their tonsils can be surgically removed.
Sources: https://en.wikipedia.org/wiki/Tonsillitis, http://www.rightdiagnosis.com/t/tonsilitis/prevalence-types.htm, http://www.nhs.uk/Conditions/Tonsillitis/Pages/Treatment.aspx, http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072482/, http://emedicine.medscape.com/article/228936-overview#a3