What Is Reactive Arthritis and Its Link to STIs

Reactive arthritis makes your joints hurt and swell after some infections. This can happen after a sexually transmitted infection, like chlamydia.

Other infections, like gonorrhea and HIV, can also cause it. Most people with an STI do not get reactive arthritis. You cannot catch this condition from another person.

• Studies show that 3% to 8.1% of people with sexually spread infections get this arthritis.
• Scientists still need more information, especially about chlamydia.

Knowing about it early helps you control symptoms and get help fast.

Key Takeaways

• Reactive arthritis can happen after infections. It often follows sexually transmitted infections like chlamydia. Look for joint pain and swelling after you get sick.
• Getting diagnosed early is very important. If you have joint pain, red eyes, or trouble peeing after an infection, see your doctor soon.
• Safe sex helps lower your chance of getting STIs. Using condoms and having regular checkups can keep you healthy.
• Knowing your family history matters. If someone in your family has the HLA-B27 gene, you might have a higher risk for reactive arthritis.
• Most people get better from reactive arthritis in a few months. Staying active and learning about your condition can help you handle symptoms well.

About Reactive Arthritis

What It Is

Reactive arthritis is when your joints get sore after an infection. You might feel pain, swelling, or stiffness in your joints. This problem often happens in your knees, ankles, or feet.

Doctors call it “reactive” because your body reacts to an infection somewhere else. The infection is not inside the joint.

You can spot reactive arthritis by looking for certain symptoms. Doctors sometimes call these the “classic triad.” This means you might have joint pain, eye problems, and trouble peeing. Not everyone gets all three, but many people have at least one.

Here is a table that lists the main signs:

You might also see other signs. These can be swollen fingers or toes, pain where tendons meet bones, or changes in your skin. Sometimes, you might get mouth sores or nail changes.

If your joints hurt and you have other symptoms after being sick, tell your doctor. Getting help early can make you feel better sooner.

How It Starts

Reactive arthritis often begins after you have had an infection. This can be a sexually transmitted infection like chlamydia. Your symptoms usually start one to three weeks after the infection. Sometimes, you may not notice the first infection if it was mild or had no signs.

Here is a table that shows when symptoms usually start:

The first things you might notice are:

• Pain and swelling in one or a few joints, often knees or ankles
• Red, itchy, or sore eyes
• Pain when you pee or genital discharge
• Swollen fingers or toes that look like sausages
• Feeling tired, having a fever, or feeling sick

You might also feel pain where tendons join bones, called enthesitis. Sometimes, you get rashes or mouth sores. These problems can be mild or very bad.

Most people start to feel better after a few months. Some people may have symptoms that come back later.

Not everyone who gets an infection will get reactive arthritis. Your risk depends on your genes, your immune system, and the kind of infection you had.

Causes and STI Link

STIs That Trigger It

You might wonder which infections can cause reactive arthritis. Some sexually transmitted infections are more likely to cause this problem than others. If you get an infection in your genital area, your immune system might react. This reaction can make your joints hurt and swell.

Here are the main STIs linked to reactive arthritis:

• Chlamydia trachomatis: This infection is the most common cause. It causes up to two-thirds of all cases.
• Neisseria gonorrhoeae: Gonorrhea can also cause reactive arthritis. Reports say it causes up to 16% of cases.
• HIV: People with HIV have a higher chance of getting reactive arthritis.

Doctors call it “sexually acquired reactive arthritis” (SARA) when it happens after an infection in the genital area. You do not need to have symptoms from the STI for reactive arthritis to happen. Sometimes, the infection is so mild you do not notice it.

Reactive arthritis is a type of sterile inflammatory arthritis. This means your joints get inflamed, but doctors do not find bacteria in the joint fluid.

Symptoms can start a few weeks after the infection. The risk is higher if you have certain genes, like HLA-B27. People with this gene are five times more likely to get reactive arthritis than people without it.

Why the Body Reacts

Your body reacts to some infections by making your joints inflamed. Scientists think your immune system is very important in this process.

When you get an STI like chlamydia, your immune cells fight the bacteria. Sometimes, pieces of the bacteria, called antigens, travel to your joints. Even if doctors cannot find live bacteria in your joints, these antigens can still cause problems.

Your immune system makes special proteins called cytokines. These proteins help control inflammation. In reactive arthritis, the amount of cytokines changes. Some important cytokines are IL-17, IL-12, IL-23, IL-6, TNF-α, IFN-γ, and IL-10. Too many of these proteins can make your joints hurt and swell.

Genes are important too. If you have the HLA-B27 gene, your immune system may react more strongly to infections. Studies show that 60–90% of people with reactive arthritis in the UK in the 1960s and 1970s had this gene. If your family has this gene, your risk is even higher.

Your risk of reactive arthritis depends on your genes, your immune system, and the kind of infection you get.

You may not be able to stop your immune system from reacting, but knowing what causes it helps you understand why symptoms show up after an STI.

Who Is at Risk

Main Risk Factors

You might ask what makes someone more likely to get reactive arthritis. There are a few things that can raise your chances. Doing unsafe sexual things can make it easier to get infections. These infections can lead to joint problems. Not keeping clean can also cause more infections.

This can make your joints hurt. Eating lots of sugar and fat is not good for your joints. It can make swelling worse if you already have pain.

Here is a table that lists the main risk factors:

Your genes matter too. If you have the HLA-B27 gene, your risk is higher. Most people with reactive arthritis have this gene. People with HIV might get joint pain as their first sign of infection.

Not everyone who gets an STI will have joint problems. Your risk depends on what you do, your genes, and your immune system.

Gender and Age

Men are much more likely to get reactive arthritis after an STI than women. Men are nine times more likely to get it from sexual activity. If the cause is a stomach infection, men and women have the same risk.

Most people who get reactive arthritis from an STI are young adults. The usual age is between 20 and 40 years old. Young men are the group that gets this condition the most.

Here is a table that shows who is most at risk:

If you are a young adult man and have had an STI, watch for joint pain or swelling. Getting help early can make you feel better faster.

Diagnosing Reactive Arthritis

Symptoms

You may notice several signs if you have reactive arthritis. These symptoms often appear a few weeks after an infection. The most common problems affect your joints, eyes, skin, and urinary tract.

You might feel pain or swelling in your knees, ankles, or heels. Sometimes, your toes or fingers swell up and look like sausages. You could also have pain in your lower back, especially at night or in the morning.

Here is a table that shows the main symptoms:

You might also notice:

• Painful or frequent urination
• Red or sore eyes
• Rashes on your hands, feet, or penis
• Diarrhea or stomach upset

If you see these symptoms after an infection, talk to your doctor. Early diagnosis can help you feel better faster.

Medical Tests

Doctors use several tests to find out if you have reactive arthritis. They start by asking about your symptoms and recent infections. A physical exam helps them check your joints, eyes, and skin.

Some common tests include:

• Blood tests: These can show signs of inflammation. Doctors may look for the HLA-B27 gene. About 8% of people have this gene, but it appears in up to 96% of people with this condition.
• Joint fluid analysis: Doctors take a small sample of fluid from a swollen joint. This test checks for infection. In reactive arthritis, the fluid has many white blood cells, but no bacteria.
• Urine tests: These can find signs of infection in your urinary tract.
• Imaging tests: X-rays or ultrasounds can show swelling or damage in your joints.

Here is a table that shows how effective some tests are:

Your doctor may use more than one test to make sure you get the right diagnosis. Getting tested early helps you start treatment sooner.

Treatment and Recovery

Medications

There are different ways to treat reactive arthritis. Doctors usually give medicine to help with pain and swelling. Here is a table that lists the main medicines and what they do:

Doctors might give you antibiotics if you have an infection like chlamydia. Some studies show that taking two antibiotics for six months helps many people. About 63% of people felt better with antibiotics. Only 20% got better with a fake pill. Some people had all their symptoms go away. But other studies found that short antibiotic treatments did not work as well. Some people did not get better for a long time. How well antibiotics work depends on the kind and how long you take them.

Most people start to feel better in a few weeks or months. About half of people get better in six months or less. Some people have symptoms that last longer, even over a year.

Managing Symptoms

There are many ways to help your body heal and feel better. Non-medicine ways are important for comfort and moving around:

• Learning about your condition and how to manage it
• Using ways to relax and talking to someone if you feel stressed
• Talking to a counselor or using CBT to help your feelings
• Doing exercises with a physical therapist
• Making muscles around your joints stronger and moving your joints
• Exercising in water, which is easy on your joints

Physical therapy can help in many ways:

1. Stretching and moving your joints helps stop stiffness.
2. Isometric exercises make muscles stronger without moving joints.
3. Strengthening exercises help you move and keep your balance.
4. Manual therapy helps your joints move better.
5. Water therapy lets you exercise without hurting your joints.
6. Fixing your posture can help with pain.
7. Learning more can help you stop flare-ups.

Most people have strong symptoms for a few weeks to six months. Many get better in three to four months. Some people have joint pain that comes back for years.

About 15–30% of people can get long-lasting arthritis or other problems. Most people can live normal lives. Most symptoms go away in a year, but about 25% of people may have problems that last longer.

Keep moving and learn about your condition. This can help you feel better and live well.

Reactive arthritis can happen after infections like chlamydia or gonorrhea. You might feel pain in your joints. Your eyes may hurt or look red. You could have trouble when you pee. Here are some important things to know:

• Reactive arthritis is often caused by sexually transmitted infections, mostly Chlamydia trachomatis.
• Using condoms and having safe sex can help protect you.
• Finding and treating the problem early can stop it from getting worse.
• If you feel sick after an infection, watch for signs and tell your doctor.

Learning more helps you spot symptoms sooner and get better faster. Groups like the Arthritis Foundation can give you more help and information.

FAQ

What is the main cause of reactive arthritis?

You usually get reactive arthritis after an infection. The most common cause is a sexually transmitted infection like chlamydia. Your immune system reacts to the infection and causes joint pain and swelling.

What symptoms should you watch for?

Look for joint pain, swelling, red or sore eyes, and pain when you pee. You might also see rashes or swollen fingers. If you notice these signs after an infection, talk to your doctor.

What tests help diagnose reactive arthritis?

Doctors use blood tests, joint fluid analysis, urine tests, and imaging like X-rays. These tests help find inflammation and rule out other causes. Your doctor may also check for the HLA-B27 gene.

What can you do to lower your risk?

Practice safe sex by using condoms. Get regular STI screenings. Treat infections early. Learn about your family history, especially if someone has the HLA-B27 gene. Healthy habits help protect your joints.