Post-streptococcal reactive arthritis (PSRA): What to know

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PSRA is arthritis in one or more joints that develops after someone has had a Group A streptococcal infection (GAS). According to a 2020 study, these bacteria are the most common cause of pharyngitis (throat inflammation), otherwise known as strep throat.

This type of arthritis typically occurs 7–10 days after an infection, and it is more common in people ages 8–14 and 21 –37. PRSA occurs without gender preference.

In an interview with Medical News Today, Dr. Isabelle Amigues, founder of UnabridgedMD, adds that PSRA is an autoimmune response to GAS. Autoimmune means the immune system attacks the body’s healthy tissues, leading to various symptoms.

How common is PSRA?

PRSA is uncommon. Approximately 1–2 per 100,000 people in the United States develop the condition. This may be because improved testing can identify strep early and with immediate results. Prompt treatment for strep with antibiotics can help prevent cases of PSRA.

Learn more about autoimmune conditions.

Arthritis symptoms can vary and can be very painful. The pattern of arthritis varies; it can affect one or many joints at once and joints on both sides of the body. Another form of arthritis called dactylitis can cause swelling of the whole finger or toes.

PSRA is less likely to lead to residual joint damage or deformities.

Morning stiffness and nighttime pain are also typical.

PSRA can also cause non-joint symptoms, including:

• erythema nodosum — which are red, tender, raised nodules deep in the skin
• glomerulonephritis — inflammation of a kidney
• uveitis — inflammation of the middle layer of eye tissues

Other non-joint symptoms, such as carditis (heart inflammation) can occur.

How long does PSRA last?

Typically, PSRA lasts about 2 months but may range from 1 week to 8 months.

Learn more about arthritis types and symptoms.

Although a throat infection with GAS may cause PSRA, it can also cause a similar condition called acute rheumatic fever (ARF). Sometimes, doctors find it challenging to make a differential diagnosis between the two conditions.

Amigues explains the distinguishing features:

• PSRA develops in 1–2 weeks after the infection, as opposed to 4–5 weeks in ARF.
• The response to treatment with anti-inflammatory drugs is less obvious with PSRA.
• Markers of inflammation are lower than with PSRA.
• While the two conditions have symptoms in common, they have some differences.
• PSRA arthritis tends to be more prolonged than arthritis in ARF.

“Doctors endeavor to diagnose PSRA when it occurs, but it may actually be a milder form of ARF,” adds Amigues.

Learn more about inflammation.

Evidence indicates that treatment typically involves nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Motrin). A person should take this medication for at least 1 year.

“Once we confirm a diagnosis of PSRA, if NSAIDs do not provide enough symptom relief, we may recommend some biologic agents,” said Amigues. “These may entail tumor necrosis factor (TNF) inhibitors, such as adalimumab (Humira).” TNF inhibitors reduce inflammation in autoimmune conditions.

“There are instances when it is not absolutely clear whether someone has PSRA or ARF,” added Amigues. “In these cases, some doctors favor prescribing antibiotics for 1– 2 years after the onset of symptoms to help prevent delayed-onset carditis. Carditis is a complication of PSRA and ARF. The purpose of antibiotics is to eradicate the GAS infection from the throat.”

“Afterward, these people will get a cardiac evaluation with an echocardiogram — a heart function test,” continued Amigues. “If this shows no heart abnormality, we can discontinue the antibiotics.”

Aside from drug treatment, doctors may also recommend:

• Balance of exercise and rest: Exercise can increase and maintain muscle strength and keep the joints moving and flexible.
• Assistive devices: These may include a walker or cane to make it easier for a person to move around.
• Cold and heat therapies: These interventions may reduce pain.
• Braces or shoe inserts: These can help an individual stand and walk because they provide support and may decrease pain.

Learn more about NSAIDs.

“The most dreaded complication of PSRA is carditis, which can cause inflammation in the heart valves and result in heart failure,” said Amigues. “Heart failure is the inability of the heart to pump adequately to supply circulation to the body.”

Research findings indicate that carditis happens in approximately 8% of children. The risk of this complication in adults is unclear, although an older 2009 study suggests it may not affect adults.

Learn more about heart inflammation.

“Sometimes people do not appear to have a definite diagnosis of either PSRA or ARF,” said Amigues. “When this happens, they need an evaluation by rheumatology. Indeed, we need to ensure that the symptoms are due to reactive arthritis and not some other type of inflammatory arthritis, such as rheumatoid arthritis.”

Rheumatoid arthritis can cause similar symptoms in the joints, such as:

• pain
• swelling
• morning stiffness

Additionally, like PSRA, rheumatoid arthritis may affect the eyes and heart. However, unlike PSRA, rheumatoid arthritis can involve other parts of the body, including:

• blood
• blood vessels
• lungs
• skin
• mouth

Learn more about rheumatoid arthritis.

PSRA is an autoimmune response to a strep throat infection that manifests within 7–10 days afterward.

The symptoms that can affect one or more joints include swelling and pain. They may also involve the skin, kidneys, and eyes.

Diagnosis may pose a challenge because a GAS infection may also cause ARF, which is similar to PSRA.

Treatment entails NSAIDs and may include antibiotics. The mean duration of the condition is 2 months. Carditis is a dangerous complication.

A person who develops arthritis shortly after recovering from strep throat should see a doctor for further assessment.