Sore throats and rheumatic fever: when a common illness matters

The US Centers for Disease Control and Prevention (CDC) states plainly that viruses cause most sore throats. It puts the share with strep throat at about 1 in 10 adults and 3 in 10 children with a sore throat. The NHS agrees that sore throats are usually caused by viruses such as colds or flu, and only occasionally by bacteria.

That is why the NHS says you do not normally need antibiotics for a sore throat: they usually do not relieve symptoms or speed recovery. Most sore throats, it says, get better by themselves within a week. Antibiotics are a prescription decision for a pharmacist or doctor to make when a bacterial infection looks possible, and nobody should start them on their own.

Group A strep causes strep throat, a bacterial infection of the throat and tonsils that is contagious. The CDC lists fever, pain when swallowing, red and swollen tonsils, white patches or streaks of pus on the tonsils, swollen lymph nodes at the front of the neck, a sore throat that comes on quickly, and tiny red spots on the roof of the mouth. Less common signs, especially in children, include headache, nausea or vomiting, a rash (scarlet fever) and stomach pain.

Because these features overlap with viral infections, a clinician may use a test to find out which one is present. The CDC notes that providers have several types of test, including a quick one.

Rheumatic fever is described by the CDC as an immune response to an earlier bacterial infection rather than an infection itself. It can follow group A strep infections, usually about 1 to 5 weeks later, and it cannot be caught from another person. The NHS calls it a very rare complication and says most people who have a bacterial throat or skin infection do not develop it. Genes may make it more likely.

The reason it matters is the heart. The NHS says rheumatic fever can cause permanent damage to the heart, known as rheumatic heart disease. That condition is covered in rheumatic heart disease, including who is most affected and how it is managed.

The World Health Organization states that treating strep throat with appropriate antibiotics prevents rheumatic fever. The US National Heart, Lung, and Blood Institute (NHLBI) makes the same point from the heart's side: completing strep throat treatment helps prevent rheumatic fever, which can damage the heart valves. Those statements apply to a course that a clinician has diagnosed and prescribed, taken as directed.

The NHS adds that people who have had rheumatic fever are more likely to get it again, so they should have sore throats treated early, and some need antibiotics for several years to prevent a recurrence. If you want to see what valve damage does to the heart, read heart valve problems.

The NHS says symptoms usually start 1 to 5 weeks after a bacterial throat infection. It lists:

• a high temperature
• painful, swollen joints, usually ankles, knees, wrists or elbows
• chest pain, breathlessness and a fast heart rate
• jerky, uncontrollable movements of the hands, feet and face
• small bumps under the skin
• pale-red patches on the arms and abdomen

The CDC describes the same picture, noting that tender joints (knees, ankles, elbows, wrists), jerky movements, tiredness and fever are the common features, while a new heart murmur, an enlarged heart or fluid around the heart can signal heart involvement. The CDC says it is most often seen in school-age children, 5 to 15 years old, and is rare in children under 3 and in adults.

Chest pain and breathlessness have many possible causes, so this list is a prompt to get assessed rather than a way to diagnose anything. Our guide to how the heart works gives background on the valves and chambers involved.

The NHS suggests seeing a GP if you have had rheumatic fever before and get a sore throat, if you think it has returned, or if you develop its symptoms after a recent bacterial throat infection. For an ordinary sore throat, the NHS advises an urgent appointment or NHS 111 if there is a very high temperature, signs of dehydration or a weakened immune system, and emergency care for difficulty breathing or swallowing, drooling or a high-pitched sound when breathing. Services and emergency numbers differ between countries, so use your local equivalents.

Most sore throats are viral and settle within about a week. A minority are strep throat, and a very small number of those lead to rheumatic fever and possible heart valve damage. Prompt assessment by a clinician and finishing any antibiotic course that is prescribed are how the risk is reduced; self-prescribing is never the answer.