Several sexually transmitted infections can cause joint pain, but the two most common culprits are gonorrhea and chlamydia. Gonorrhea can directly infect a joint, causing rapid swelling and severe pain. Chlamydia triggers joint pain through a different mechanism, provoking an immune overreaction called reactive arthritis that inflames joints days to weeks after the initial infection. Hepatitis B, hepatitis C, syphilis, and HIV can also cause joint symptoms at various stages.
Gonorrhea: The Most Direct Cause
Gonorrhea is the STD most likely to cause sudden, severe joint pain. In roughly 0.5% to 3% of gonorrhea cases, the bacteria escape the original site of infection and spread through the bloodstream, a condition called disseminated gonococcal infection (DGI). Once that happens, 42% to 85% of those patients develop septic arthritis, where bacteria are actively growing inside the joint.
DGI tends to hit the knees, ankles, elbows, fingers, and toes. The pain often migrates, flaring in one joint and then moving to another. It typically shows up in one of two patterns. The first involves a combination of skin lesions (small red or pus-filled spots), tendon inflammation, and shifting joint pain. The second is a single, intensely swollen and painful joint with no skin involvement. Both patterns can develop even when the original genital, rectal, or throat infection caused no noticeable symptoms at all.
A joint that becomes hot, swollen, and extremely painful over a matter of hours is a red flag. Septic arthritis can damage cartilage quickly if untreated, but it responds well to antibiotics when caught early. The CDC recommends hospitalization for initial treatment of DGI, and doctors will typically test fluid drawn directly from the swollen joint to confirm the diagnosis. Standard cultures only detect the bacteria about half the time, so more sensitive genetic tests (NAATs) are often used alongside them.
Chlamydia and Reactive Arthritis
Chlamydia doesn’t usually infect the joint itself. Instead, it triggers reactive arthritis, an inflammatory condition where the immune system attacks joint tissue after fighting off the initial infection. The classic pattern involves three areas: joints, the urinary tract, and the eyes. Not everyone gets all three, but joint pain is the hallmark symptom.
The timeline is distinctive. Genital symptoms typically appear first, followed by joint inflammation about two weeks later, though the gap can range from three days to six weeks. The arthritis usually affects a small number of joints asymmetrically, often in the knees, ankles, or feet. Unlike rheumatoid arthritis, which tends to hit the same joints on both sides of the body, reactive arthritis is lopsided.
For most people, the initial flare resolves within three to four months. But the long-term picture is less reassuring: up to 50% of people with chlamydia-triggered reactive arthritis experience recurring joint inflammation over several years. People who carry a specific genetic marker called HLA-B27 are at higher risk for chronic symptoms. In persistent cases, the inflammation can eventually cause joint deformities or damage to the spine and sacroiliac joints. Some people develop permanent disability.
Hepatitis B and Hepatitis C
Joint pain and arthritis occur in up to 50% of people during the early phase of hepatitis B infection, often before jaundice or other liver symptoms appear. The pattern is typically symmetrical, affecting small joints in the hands and feet. It may come with hive-like or reddish skin lesions on the legs. Both the joint pain and skin changes usually resolve once jaundice develops, though some people with chronic hepatitis B continue to have recurring asymmetrical joint inflammation.
Hepatitis C causes joint problems through a different pathway. The virus stimulates certain immune cells to overproduce antibodies and abnormal proteins called cryoglobulins, which deposit in blood vessels and joints. The resulting arthritis is bilateral and symmetrical, primarily targeting the small joints of the hands and wrists in a pattern that closely mimics rheumatoid arthritis. This resemblance can lead to misdiagnosis, especially if hepatitis C hasn’t been identified yet. Knees are also commonly affected.
Syphilis Joint Involvement
Syphilis can cause joint problems at nearly any stage of the disease, though it’s most associated with the later stages. In secondary and tertiary syphilis, the bacteria provoke inflammation of the tissue lining the joints, resulting in migratory pain that shifts between joints. The most commonly affected areas are the knees, hips, shoulders, and finger joints. Swelling, tenderness, and reduced range of motion are typical.
Tertiary syphilis, which develops years after the initial infection if left untreated, can cause two distinct forms of joint damage. One involves chronic inflammation of the joint lining. The other is an erosive process that eats into the bone surface, creating irregular, damaged joint surfaces. In the most advanced cases, syphilis damages the nerves that supply a joint, leading to a type of progressive, painless joint destruction called neuropathic arthropathy. Joint-lining inflammation responds well to antibiotics, but nerve-related joint damage does not.
HIV and Joint Pain
During the acute phase of HIV infection, the first few weeks after exposure, many people experience flu-like symptoms that can include muscle aches and joint pain. Later in the course of HIV, various forms of arthritis can develop, including reactive arthritis and a painful condition affecting multiple joints. Antiretroviral treatment has changed the picture significantly, but joint complaints remain common among people living with HIV.
How STD-Related Joint Pain Differs From Other Causes
The timing and context are the biggest clues. STD-related joint pain tends to come on relatively fast, over days rather than the gradual onset typical of osteoarthritis or rheumatoid arthritis. A new sexual partner in the weeks before symptoms, any recent genital discharge or burning, skin rashes, or eye redness all raise the likelihood that an STD is involved.
Septic arthritis from gonorrhea is especially distinctive: it produces intense pain, warmth, and swelling in one or a few joints, often with fever, and it worsens rapidly. Reactive arthritis from chlamydia tends to be less explosive but still comes on faster than autoimmune conditions. Hepatitis-related arthritis can be trickier because its symmetrical pattern looks a lot like rheumatoid arthritis, but liver function tests and hepatitis screening will reveal the difference.
When doctors suspect an STD is behind joint symptoms, they’ll typically test for multiple infections at once, including gonorrhea, chlamydia, syphilis, HIV, and hepatitis. If a single joint is severely swollen, drawing fluid from it with a needle is essential to rule out active bacterial infection inside the joint. A confirmed STD-related arthritis that involves direct bacterial infection needs prompt antibiotic treatment to prevent permanent joint damage, while reactive arthritis is managed primarily with anti-inflammatory medications as the immune response runs its course.