Bacterial throat infection (pharyngitis)

Streptococcal pharyngitis (strep throat) is a bacterial throat infection, which normally causes sore throat, difficulty swallowing and a high temperature. It is caused by bacteria from the group A Streptococcus genus of bacteria – in most cases Streptococcus pyogenes.

This type of bacterial throat infection is much less common among adults than among children and adolescents. It tends to occur most frequently in winter and spring.

In most cases, however, throat infections are caused by viruses.

Throat infections are contagious. Those infected should avoid close contact with others to avoid spreading the illness.

Common symptoms of a bacterial throat infection caused by streptococcal bacteria are as follows:

• sore throat
• difficulty swallowing
• high temperature (fever)
• swollen lymph nodes

Among children in particular, other symptoms may include headache, stomach ache, nausea and vomiting.

Symptoms typically develop very quickly. Each of these symptoms can vary widely and can occur independently of the others.

A bacterial throat infection is usually caused by the Streptococcus pyogenes pathogen – a member of the group A Streptococcus genus of bacteria. These bacteria are transmitted from person to person.

They are generally contracted through close direct contact with people who are infected. The pathogens are transmitted by droplets when coughing, sneezing or talking, for example. If these pathogenic droplets get onto the mucous membranes in the nose, mouth or eyes, people can become infected.

It is also possible to become infected through indirect contact when touching contaminated door handles or toys, for example. This is another type of smear infection. 

In very rare cases, group A Streptococcus bacteria are spread via food or water.

In general, more people contract strep throat during the months of winter and spring.

This type of infection occurs most commonly between the ages of 5 and 15. Strep throat causes up to 30 percent of all cases of throat infections in this age group. In adults, this figure is only about 10 percent.

A bacteria throat infection is very rare in children younger than 3.

In general, an acute bacterial throat infection with streptococcal bacteria heals on its own and most symptoms disappear after one week.

However, secondary conditions or complications may occur in rare cases. These include:

• tonsillitis
• pus accumulation around the palatine tonsils (peritonsillar abscess)
• middle ear infection
• meningitis
• pneumonia
• blood poisoning (sepsis)
• endocarditis (inflammation of the lining of the heart)
• rheumatic fever
• kidney inflammation (glomerulonephritis)

Treatment with antibiotics that can effectively combat streptococci can help people recover from the illness slightly quicker. People treated with antibiotics are no longer contagious once they have been symptom-free for at least 24 hours. To date, there is no clear proof of whether antibiotics can also reliably prevent secondary conditions and complications.

There is no vaccine against streptococcal throat infections.

However, there are a number of simple steps that people can take to avoid infection. For example, they can

• avoid contact with people who have an acute illness
• wash hands thoroughly and often with soap and warm water
• frequently disinfect items like toys and door handles

Anyone who has already recovered from a streptococcal secondary condition such as rheumatic fever, can, however, also protect themselves in further ways. In consultation with a doctor, antibiotic prevention over several years can be considered to prevent a new infection.

Doctors are generally unable to tell whether a throat infection has been triggered by streptococci based on a patient’s symptoms alone.

They can therefore also use a throat swab. The sample taken can be analyzed on-site at the doctor’s practice using a rapid screening test or sent for testing in a lab. If the result of the rapid strep screen is negative, it may be useful to have another throat swab analyzed in the lab. It can sometimes be useful to provide proof of the bacteria, but this is not always required.

Even if the throat infection has been caused by bacteria, patients do not necessarily need to take antibiotics. Doctors can decide whether or not the administration of an antibiotic is useful based on a patient’s symptoms and medical history.

Penicillin or amoxicillin in tablet form are most commonly used to treat strep throat. Other antibiotics can be used for anyone who is allergic to penicillins.

In most cases, the symptoms disappear at latest on the third day of treatment with antibiotics. Despite this, it’s important to continue taking the tablets for the full period prescribed by the doctor. Otherwise, the infection may not clear up completely and may flare up again.

In the case of severe pain or fever, medication to relieve pain and reduce temperature can also be taken (e.g paracetamol or ibuprofen).

Some people suffer acute strep throat on a recurring basis. The tonsils may also become inflamed (tonsillitis). If this happens frequently or if the symptoms are severe, surgical removal of the tonsils may be considered. It is also possible to only remove part of the tonsils.

Other important measures

People with a streptococcal infection are not initially allowed to attend community facilities such as schools. This applies until they have started antibiotic treatment and not experienced any new symptoms for at least 24 hours. At that stage, people with a streptococcal infection are no longer contagious. People who do not take antibiotics can only return to community facilities at least 24 hours after all symptoms have completely subsided. The assessment of the doctor treating them is key.