Pharyngeal Abscess (Throat Abscess)

What a pharyngeal abscess is

The pharynx is surrounded by layers of tissue called fascia that create potential spaces in the neck. Lymph nodes in these spaces drain the nose, sinuses, tonsils, teeth and middle ear. When bacteria from an infection reach a node or a space, they can form an abscess: a walled-off collection of pus.

Because the spaces connect from the base of the skull to the chest, an abscess can spread downward into the mediastinum, the space around the heart. Swelling also narrows the airway. These are the reasons a throat abscess is treated as a potential emergency.

Types of pharyngeal abscess

Peritonsillar abscess is by far the most common. Retropharyngeal abscess is most common in young children because they have lymph nodes behind the pharynx that shrink after about age 5. In adults it more often follows an injury from a fish bone, a chicken bone, a fall with a pen or stick in the mouth, or medical instruments.

Infections that spread under the tongue and floor of the mouth, from a lower molar tooth, are a related emergency called Ludwig angina.

Symptoms of a pharyngeal abscess

• A severe sore throat that gets worse over 2 to 5 days rather than better
• Pain or difficulty swallowing, sometimes so bad that saliva is spat out or drools
• Fever and feeling very unwell
• A muffled or "hot potato" voice
• Neck pain and stiffness, and refusing to turn or extend the neck
• Difficulty opening the mouth (trismus)
• Swollen, tender lymph nodes in the neck
• Bad breath and pain spreading to the ear on the same side
• In severe cases, noisy breathing (stridor) or breathlessness

In young children, the signs can be less specific: fever, irritability, poor feeding, drooling and holding the neck stiffly. This can be mistaken for meningitis.

Causes and risk factors

Most pharyngeal abscesses are mixed infections, often including Streptococcus pyogenes (group A strep), Staphylococcus aureus (including MRSA) and anaerobic bacteria from the mouth.

They develop from:

• tonsillitis and strep throat that are untreated or partly treated
• upper respiratory infections and ear or sinus infections in children
• dental infections, especially of the lower back teeth
• a penetrating injury to the back of the throat
• spread from infected neck lymph nodes

Smoking, poor dental health, diabetes and a weakened immune system raise the risk.

How it is diagnosed

1. Examination: the doctor looks at the throat, the position of the uvula and tonsils, the mouth opening, neck movement and the breathing. If the airway looks at risk, examination is kept to a minimum and done where the airway can be secured.
2. CT scan of the neck with contrast: the main test. It shows whether there is an abscess (pus) or only cellulitis (swollen, inflamed tissue without pus), its exact location and whether it has spread.
3. Neck X-ray: a side view can show widening of the tissue in front of the spine in a retropharyngeal abscess.
4. Blood tests: white cell count, inflammatory markers and blood cultures.
5. Needle aspiration: for a peritonsillar abscess, drawing pus with a needle both confirms and treats it.

Doctors also distinguish an abscess from epiglottitis, which causes similar drooling and breathing problems but affects the flap above the voice box.

Treatment

Airway first

If breathing is threatened, the airway is secured in the operating room or intensive care unit, sometimes with a breathing tube placed through the nose or, rarely, a surgical airway.

Antibiotics

IV antibiotics that cover streptococci, staphylococci and anaerobes are started straight away, then switched to tablets once the person improves, for a total course of about 2 weeks. Small retropharyngeal abscesses in children, and early infections that are still cellulitis, often settle with antibiotics alone.

Drainage

• Peritonsillar abscess: needle aspiration or a small cut under local anesthetic, usually in the emergency department or ENT clinic.
• Retropharyngeal and parapharyngeal abscesses: surgical drainage through the mouth or through the neck under general anesthetic when the collection is large, not responding to antibiotics or threatening the airway.

Supportive care

IV fluids for dehydration, pain relief, and sometimes a short course of steroids to reduce swelling. Hospital stays usually last 2 to 5 days.

Complications

• Airway obstruction
• Spread to the chest (mediastinitis) or around the heart
• Rupture of the abscess and inhalation of pus, causing pneumonia
• Clot in the jugular vein (Lemierre syndrome)
• Erosion into the carotid artery (rare)
• Sepsis

With early treatment, complications are uncommon and most people recover fully.

Outlook and prevention

Most people feel better within 48 hours of drainage and antibiotics. A peritonsillar abscess comes back in roughly 1 in 10 people. If it recurs, or if there is a history of frequent tonsillitis, a tonsillectomy is usually recommended. Treating strep throat properly, keeping up with dental care and getting early help for a sore throat that keeps worsening reduce the risk.

Frequently asked questions

What is a pharyngeal abscess?

It is a collection of pus in the deep tissues around the throat, usually spreading from tonsillitis, a dental infection or a throat injury. The main types are peritonsillar, retropharyngeal and parapharyngeal. It causes severe sore throat, fever and difficulty swallowing, and needs urgent medical treatment.

Is a pharyngeal abscess dangerous?

It can be. The swelling can narrow the airway, and the infection can spread down the neck into the chest or into the blood. With prompt antibiotics and drainage, most people recover fully within 1 to 2 weeks. Never ignore drooling or noisy breathing.

How is a retropharyngeal abscess different from a peritonsillar abscess?

A retropharyngeal abscess sits behind the back wall of the throat and mainly affects young children, causing neck stiffness and drooling. A peritonsillar abscess sits beside one tonsil, mainly affects teenagers and young adults, and causes one-sided throat pain and difficulty opening the mouth.

Can a throat abscess go away on its own?

Rarely, and it should not be left to try. Some small abscesses and early infections settle with antibiotics alone, but most need the pus drained. Untreated, an abscess can burst into the throat or spread to dangerous areas of the neck and chest.

How long does it take to recover from a pharyngeal abscess?

Pain and fever usually improve within 1 to 2 days of drainage and antibiotics. Most people leave hospital within a few days and finish about 2 weeks of antibiotics. Normal eating and activity usually return within 1 to 2 weeks.