Tonsillitis is inflammation of the tonsils. It's usually caused by a viral infection or, less commonly, a bacterial infection.

Tonsillitis is a common condition in children, teenagers and young adults.

Symptoms of tonsillitis

The symptoms of tonsillitis include:

• a sore throat and pain when swallowing

• earache

• high temperature (fever) over 38C (100.4F)

• coughing

• headache

Symptoms usually pass within three to four days.

When to see your GP

Tonsillitis isn't usually a serious condition. You only need to see your GP if symptoms:

• last longer than four days and don't show any signs of improvement

• are severe – for example, if you're unable to eat or drink due to the pain, or you have difficulty breathing

Your GP will examine your throat and ask you some questions about your symptoms. If necessary, a throat swab can be taken to confirm the diagnosis. The results usually take a few days to return.

If your tonsillitis is caused by a bacterial infection, they may prescribe antibiotics. Typical signs of a bacterial infection include white pus-filled spots on the tonsils, no cough and swollen or tender lymph glands.

If you develop severe tonsillitis as a teenager or adult, your GP may recommend a blood test for glandular fever.

The tonsils

The tonsils are two small glands that sit on either side of the throat. In young children, they help to fight germs and act as a barrier against infection.

When the tonsils become infected, they isolate the infection and stop it spreading further into the body.

As a child's immune system develops and gets stronger, the tonsils become less important and usually shrink. In most people, the body is able to fight infection without the tonsils.

Removal of the tonsils is usually only recommended if they're causing problems, such as severe or repeated episodes of tonsillitis.

What causes tonsillitis?

Most cases of tonsillitis are caused by a viral infection, such as the viruses that cause the common cold or flu virus (influenza).

Some cases can also be caused by a bacterial infection, typically a strain of bacteria called group A streptococcus bacteria.

These types of infections spread easily, so it's important to try to avoid passing the infection on to others by:

• staying away from public places, such as work, school or nursery, until your GP says it's safe to return (usually after the symptoms have passed)

• coughing and sneezing into a tissue and disposing of the tissue

• washing hands before eating, after going to the toilet and, if possible, after coughing and sneezing

Treating tonsillitis

There's no specific treatment for tonsillitis, but you may be able to reduce the symptoms by:

• taking paracetamol or ibuprofen to help relieve pain

• drinking plenty of fluids

• getting plenty of rest

If test results show that your tonsillitis is caused by a bacterial infection, a short course of oral antibiotics may be prescribed.

If oral antibiotics aren't effective at treating bacterial tonsillitis, intravenous antibiotics (given directly into a vein) may be needed in hospital.

Chronic tonsillitis

In most cases, tonsillitis gets better within a week. However, a small number of children and adults have tonsillitis for longer, or it keeps returning. This is known as chronic tonsillitis and surgical treatment may be needed.

Surgery to remove the tonsils (a tonsillectomy) is usually only recommended if:

• you've had several severe episodes of tonsillitis over a long period of time

• repeated episodes are disrupting normal activities

Complications of tonsillitis

Complications of tonsillitis are rare and usually only occur if it's caused by a bacterial infection. They're usually the result of the infection spreading to another part of the body.

Possible complications of tonsillitis include:

• a middle ear infection (otitis media) – where fluid between the eardrum and inner ear becomes infected by bacteria

• quinsy (peritonsillar abscess) – an abscess (collection of pus) that develops between one of the tonsils and the wall of the throat

• obstructive sleep apnoea (OSA) – where the walls of the throat relax during sleep, which causes breathing difficulties and poor sleep

Other complications of tonsillitis are very rare and usually only occur if an underlying bacterial infection is left untreated. They include:

• scarlet fever – a condition that causes a distinctive pink-red skin rash

• rheumatic fever – this causes widespread inflammation throughout the body, leading to symptoms such as joint pain, rashes and jerky body movements

• glomerulonephritis – an infection (swelling) of the filters in the kidneys that can cause vomiting and a loss of appetite