Subcutaneous nodules in rheumatic fever are firm, painless lesions that appear under the skin covering joints. Rheumatic fever is an inflammatory condition that can affect the joints, heart, brain, and skin.

The nodules most commonly manifest in people who have the heart effects. These skin manifestations usually disappear without treatment.

Rheumatic fever is a delayed response to a group A Streptococcus (GAS) infection of the throat, called strep throat, or a GAS infection of the skin.

This article explains what subcutaneous nodules in rheumatic fever are, including their symptoms, causes, diagnosis, treatment, outlook, prevention, and when to call a doctor.

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Subcutaneous nodules are one of the manifestations of acute rheumatic fever. They affect less than 10% of people with the condition and usually link to severe carditis, which is heart inflammation.

In fact, it is important to identify the nodules because they indicate heart valve damage and worsened severity of rheumatic fever, states a 2021 review.

What is rheumatic fever?

Rheumatic fever is an inflammatory condition that can cause swelling in the joints, heart, brain, and skin. Common symptoms include:

The incidence is highest in children between ages 5–15.

Learn more about rheumatic fever.

Symptoms of subcutaneous nodules are bumps under the skin with the following characteristics:

They most commonly affect the skin covering large joints, such as the ankles, knees, or wrists. Usually, they appear in clusters.

The cause of subcutaneous nodules is rheumatic fever.

In turn, the cause of rheumatic fever is an autoimmune reaction that stems from an earlier GAS infection of the throat or skin. Autoimmune means a person’s immune system attacks their own body tissues. The most common GAS infection that leads to rheumatic fever is strep throat.

A risk factor of rheumatic fever involves inadequate treatment of strep throat. Being in crowded conditions, such as what people experience in military barracks and day care centers, raises the risk of strep throat. This increases the likelihood of rheumatic fever and its effects, including subcutaneous nodules.

Learn more about strep throat.

Because strep throat can cause rheumatic fever — which can damage the heart — any person with a sore throat that lingers for more than a few days or worsens should seek medical attention. A doctor can test for strep throat and prescribe an antibiotic if necessary. Prompt treatment is important for preventing rheumatic fever.

Also, someone with symptoms of subcutaneous nodules should see a doctor. Although they disappear without treatment, they indicate rheumatic fever, which necessitates a doctor’s care.

Symptoms comprise the primary basis of a diagnosis. A physical examination will show bumps under the skin that have the characteristics of subcutaneous nodules. That said, since this skin manifestation links to rheumatic fever, the main basis of a diagnosis involves symptoms of rheumatic fever that follow a GAS infection.

A medical history will bring to light signs of strep throat that a person experienced recently. These may include sore throat, fever, and chills. Lab tests, such as a throat culture, may confirm a recent GAS infection.

When bumps under the skin manifest with other symptoms of rheumatic fever that follow a GAS infection, doctors diagnose them as subcutaneous nodules.

Research states that subcutaneous nodules require no treatment, as they do not cause itching or pain and gradually disappear on their own.

However, people with strep throat need a course of antibiotic treatment to get rid of the infection before it can lead to rheumatic fever. Also, people with rheumatic fever need the same treatment even if medical tests do not show evidence of a recent GAS infection.

The antibiotic of choice is penicillin, which may involve an injection of penicillin G benzathine (Bicillin L-A) or an oral prescription of amoxicillin (Amoxil, Moxilin, or Trimox).

If someone has a penicillin allergy, doctors will prescribe an antibiotic from a different class, such as cephalosporins. An example is cephalexin (Bio-Cef, Keflex, Panixine DisperDose).

Subcutaneous nodules usually go away without treatment. Their duration ranges from a few days to several months.

Since strep throat can cause rheumatic fever, which can produce subcutaneous nodules, preventing the skin manifestation involves preventing the infection. This entails washing hands frequently with soap and water for at least 20 seconds.

Prevention also includes avoiding eating or drinking out of the same dishes used by someone with an infection. Once a person washes the dishes, they are safe for others to use.

Subcutaneous nodules in rheumatic fever occur in less than 10% of people with the condition. This skin manifestation involves firm, painless bumps that appear under the skin covering larger joints.

The cause of rheumatic fever is an earlier group A Streptococcus (GAS) infection of the throat or skin, which is usually strep throat. Doctors base a diagnosis on symptoms that manifest after a recent GAS infection.

The nodules do not need treatment, as they disappear on their own.

Prevention entails taking steps to protect against strep throat, such as frequent handwashing.

Individuals with a sore throat that does not improve or worsens should check with a doctor to see if they have strep throat. If they test positive for the infection, they can receive treatment that may prevent rheumatic fever.