What Does a Hot Joint Mean?

Knowing When It Is Time to See a Doctor

Woman touching warm, red ankle.
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The warmth of a joint can tell you many things. Generally speaking, if a joint is warm enough to catch your attention, it is something you shouldn't ignore. While joint warmth can occur if you are recovering from a joint injury—during which the body will respond with inflammation—it can also foreshadow a condition or disease that needs immediate attention.

Joint warmth doesn't usually occur on its own and will often be accompanied by pain, stiffness, and swelling. These and other symptoms can provide clues as to what the cause may be, broadly described as being either traumatic, infectious, or rheumatic.

Traumatic Causes and Symptoms

Joint trauma is a term used to describe an acute injury rather that one which develops over time. These typically occur as result of sports, a fall, or a blunt force impact. The trauma may affect the bone, muscles, tendons, ligaments, cartilage, and other structures within the joint.

Among some of the more common joint injuries:

  • Dislocation, also referred to a luxation, occurs when the bones of a joint are either fully or partially separated.
  • Fracture is used to describe a broken bone.
  • Sprains occur when the ligaments that hold the joint bones together are damaged or partially torn by overstretching or twisting.
  • Strains occur when a muscle or tendon is damaged or partially torn ("pulled") by overstretching or an excessive contraction.

Some of these injuries can occur together. They most typically involve the ankle, knee, wrist, and shoulder. One of the most common is an anterior cruciate ligament (ACL) tear, commonly seen in athletes, in which a torn knee ligament prevents the shinbone sliding forward.

While the pain from a traumatic injury will usually be immediate, it can sometimes feel like a minor knock at the onset, only to progressively worsen over the course of hours or days. In addition to joint warmth, there may be bruising, stiffness, swelling, pain, and joint deformity.

Infectious Causes and Symptoms

Infections of the joint may be caused by a penetrating injury that introduces a pathogen, most often a bacteria, into the joint space or be the consequence of a systemic (whole-body) infection in which the joint is collaterally affected.

Among some of the infections in which joint warmth is symptomatic:

  • Cellulitis is a serious and potentially life-threatening infection caused by the introduction of certain bacteria into the skin. It can spread rapidly, causing rash, swelling, tenderness, and abnormally hot skin.
  • Lyme disease is a tick-borne illness caused by the bacterium Borrelia burgdorferi. Joint pain and weakness are characteristic of the infection alongside a characteristic "bull's eye" rash, fatigue, and flu-like symptoms.
  • Osteomyelitis can occur when a bacterial infection elsewhere in the body, such as a urinary tract infection or pneumonia, spreads to the bones. It can also occur as a result of a bone fracture or surgical procedure. People with diabetes are especially vulnerable.
  • Reactive arthritis is a form of arthritis that develops in response to a bacterial infection established elsewhere in the body, often days or weeks earlier.
  • Rheumatic fever is an uncommon illness associated with inadequately treated strep throat or scarlet fever. Multiple-joint inflammation is one of the tell-tale signs of the disease.
  • Septic arthritis is the inflammation of a joint due to a systemic bacterial or fungal infection. It is most often the result of a penetrating injury near or above a joint and can also be caused by the contamination of a surgical wound.

Joint warmth is often one of the first symptoms of a joint infection. What connects all of these infections the presence of fever (ranging from mild to high-grade) and malaise (a generalized feeling of unwellness). Others symptoms include joint pain, redness, swelling, and stiffness. A penetrating wound may also develop an abnormal discharge.

Seek emergency care if the joint pain is accompanied by a high fever (over 100.4 F), chills, or noticeable red streaks on the skin leading away from the infected area.

Rheumatic Causes and Symptoms

Rheumatism is a term that broadly describes any disease that causes chronic or intermittent pain and inflammation in the joints, muscles, or connective tissues. Some of these conditions are associated with age or repetitive use, while others are caused by an autoimmune disease in which the immune system attacks its own cells and tissues.

Among the conditions associated with accumulative joint damage:

  • Bursitis is the inflammation of the cushioning sac in a joint space (called a bursa), most often as the result of repetitive motion. Commonly affected areas include the knees, shoulders, elbows, and hips.
  • Osteoarthritis is the classic "wear-and-tear" arthritis in which joint cartilage is gradually worn down over time, causing joint stiffness, deformity, and restriction of motion.
  • Tendinitis is the inflammation of tendons, a condition typically associated with repetitive use. Some types are popularly referred to as tennis elbow, swimmer's shoulder, and jumper's knee.

Among the conditions caused by an autoimmune disease:

  • Gout is caused by the progressive deposit of uric acid crystals in the joint space, most predominately the big toe.
  • Juvenile idiopathic arthritis is the most common form of arthritis in children and adolescents.
  • Polymyalgia rheumatica is an inflammatory disorder most affecting people over 65 which causes pain and stiffness, especially in the shoulders.
  • Psoriatic arthritis is a form of arthritis which often develops in people with arthritis.
  • Rheumatoid arthritis is the most common form of autoimmune arthritis in which arthritic pain is most commonly bilateral (affecting joints on both sides of the body).

What characterizes all of these inflammatory disorders is the occurrence of symptom flares (also known as exacerbations). For reasons known and unknown, there will be occasional bouts of acute symptoms for which joint warmth will often be an early precipitating feature.

Even beyond the conditions themselves, some of the drugs used to treat autoimmune diseases can cause a hot joint. This is especially true of newer biologic drugs such as Enbrel (etanercept). An acute hot joint is one of the possible side effects and an early warning sign of septic arthritis.

Diagnosis

Since joint warmth rarely occurs on its own, the doctor will start by looking any other symptoms you have in conjunction with a review of your medical history, family history, current drug treatments, or any injury, infection, or medical procedure you may have recently had.

These clues can usually point the doctor in the general direction of the possible causes and help determine which tests are most appropriate. Among them:

  • A physical exam would be performed to see if there is any joint pain, rash, swelling, fever, or restriction in movement.
  • Blood tests like an erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) can detect generalized inflammation. Other blood tests can check for high levels of uric acid consistent with gout or the presence of rheumatoid factor (RF) consistent with rheumatoid arthritis.
  • Imaging tests like an ultrasound, X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) can check for bone or soft tissue damage, including dislocation, hemorrhage, or effusion (accumulation of fluids).
  • Joint aspiration (arthrocentesis) involves the removal of fluid from the joint space for microscopic evaluation in the lab.
  • Blood and tissue cultures may help isolate the bacterial or fungal cause of an infection.
  • Antinuclear antibody (ANA) tests detect specific proteins, known as autoantibodies, which are associated with the autoimmune attack.

Differentiating the possible causes may take time, but there are clues that can often help. These include whether the joint pain in bilateral or unilateral (differentiating rheumatoid arthritis from osteoarthritis), whether the event is recurrent or isolated, or whether the symptoms are limited to the joint or more constitutional (systemic).

Treatment

The treatment of a joint condition is ultimately directed by the diagnosed cause. The options can be broadly described based on whether the cause is traumatic, infectious, or rheumatic.

Treatment of Joint Injury

Mild joint injuries may only require rest, restriction of movement, ice application, and non-steroidal anti-inflammatory drugs (NSAIDs). More serious ones may require complete joint immobilization joint and intra-articular corticosteroid shot to provide short-term pain relief. Surgery may be indicated if a bone is fractured or there are ruptured tendons or ligaments that cannot heal on their own.

Joint replacement may be considered if the pain and restriction of movement are interfering with your quality of life and cannot be treated with any other means.

Treatment of Joint Infections

Joint infections, either systemic or local, are more often associated with bacteria. Mild cases may be treated with a short course of a broad-spectrum oral antibiotic. Severe bacterial infections, including those associated which septic arthritis, may require a blood culture to identify which antibiotic (or combination of antibiotics) will be most effective in resolving the infection. Hospitalization is usually required alongside intravenous fluids and vasopressor drugs to help normalize blood pressure.

Fungal infections, more commonly seen in people with compromised immune systems, are treated with antifungals, either oral or intravenous. 

Treatment of Rheumatic Disorders

Repetitive motion injuries are treated in much the same way as a traumatic injury. Osteoarthritis benefits most from the considered use of pain medications along with physical therapy, exercise, weight loss, and ice or heat application. Oral or injected corticosteroids, intra-articular hyaluronic injections, arthroscopic surgery, and joint replacement may be considered if the disease progresses.

Rheumatoid arthritis and other autoimmune joint disorders may be treated in a similar manner but may also be brought under control with disease-modifying antirheumatic drugs (DMARDs) and other biologic and targeted treatments that suppress specific parts of the immune response.

A Word From Verywell

A warm joint on its own may mean nothing or be a sign of a worrying condition. Try not to ignore it. If the symptoms persist or worsen, speak with your doctor. If needed, you may be referred to a specialist known as rheumatologist for further investigation.

On the other hand, if a joint is suddenly and excessively hot, don't wait a day or two to have it looked at. Go to your nearest walk-in clinic if your doctor unable to see you, especially if the joint is painful and swollen.

If the pain is extreme and accompanied by fever, chills, dizziness, irregular heartbeat, and rapid changes in the skin's color or appearance, seek emergency care irrespective of whether you have had a recent injury or surgical procedure. Symptoms like these rarely resolve on their own and may lead to a medical crisis if left untreated.

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