Knuckle bumps are common and vary in cause. While many are harmless, some require medical attention. Understanding potential causes helps determine when to seek advice.
Common Reasons for Knuckle Bumps
One frequent cause of a knuckle bump is a ganglion cyst. These non-cancerous, fluid-filled sacs often form near joints or tendons, including knuckles. They contain fluid similar to joint lubricant. While their exact cause is unknown, they may result from small tears in joint capsules or tendon membranes. These cysts vary in size, can change, or even disappear. They may cause pain or tenderness if they press on a nerve.
Arthritis is another common reason for knuckle bumps, with several types potentially affecting hand joints. Osteoarthritis, a degenerative joint disease, involves cartilage breakdown, leading to bone-on-bone friction. This causes pain, stiffness, and bony growths called osteophytes or bone spurs. These growths, known as Heberden’s nodes (fingertip joints) or Bouchard’s nodes (middle finger joints), create a knobbly appearance on knuckles.
Rheumatoid arthritis, an autoimmune condition, causes the immune system to attack joint linings, leading to inflammation. This results in pain, swelling, and stiffness, often affecting knuckles symmetrically. Some individuals may develop hard, rounded rheumatoid nodules under the skin near affected joints.
Psoriatic arthritis, affecting some people with psoriasis, also causes joint pain, swelling, and stiffness in the knuckles. Swelling can sometimes affect the entire finger, creating a “sausage-like” appearance known as dactylitis.
Tendinitis and bursitis involve inflammation of soft tissues around joints. Tendinitis is tendon inflammation, causing pain, swelling, and stiffness around the affected joint, often worsening with movement. Bursitis occurs when bursae, fluid-filled sacs cushioning joints, become inflamed. This can cause pain, swelling, and tenderness in hand joints, including knuckles.
Other Possible Causes
Gout is an inflammatory arthritis caused by uric acid buildup, forming sharp crystals in joints. It can cause severe pain, redness, swelling, and warmth in joints, including knuckles. Uncontrolled gout may lead to gouty tophi, hard lumps of uric acid crystals under the skin near joints.
Benign tumors can also appear as knuckle bumps. Knuckle pads are benign fibrofatty growths appearing as thickened, skin-colored nodules over finger joints. These are a type of fibromatosis, causing non-cancerous tumors under the skin. Knuckle pads can sometimes be tender or painful. Other benign growths like lipomas or fibromas may also occur.
Infections can cause swelling and pain around a knuckle. Septic arthritis, an infection within the joint, can lead to joint damage if not treated promptly. Symptoms include severe joint pain, sudden swelling, skin color changes, and a general feeling of being unwell, often with fever or chills.
When to See a Doctor
Seek medical evaluation for persistent pain or tenderness, especially if it interferes with daily activities or doesn’t improve with rest. A rapid increase in size or noticeable changes in shape, color, or texture also warrant professional assessment.
Other warning signs include warmth or redness around the bump, suggesting inflammation or infection. Consult a doctor if the bump limits finger or hand range of motion, or if you experience numbness or tingling. Any bump appearing after a significant injury, like a fall or direct impact, requires evaluation.
Medical Evaluation and Treatment
When a knuckle bump requires medical attention, a healthcare provider begins with a physical examination. This assesses the bump’s size, location, texture, and tenderness, and evaluates joint range of motion. Medical history, including previous injuries, conditions, or medications, will also be reviewed.
Imaging tests clarify the bump’s nature. X-rays identify bone spurs, fractures, or arthritis-related changes. MRI or ultrasound scans assess soft tissue anomalies like cysts or tendons. Blood tests may check for inflammatory markers or conditions like gout. If infection is suspected, joint fluid may be aspirated for analysis.
Treatment varies based on diagnosis. Conservative management is often the first approach, including rest, ice to reduce swelling, and over-the-counter pain relievers or anti-inflammatory medications. Splints or braces may be recommended to immobilize the joint and promote healing.
Injections can provide relief for certain conditions. Corticosteroid injections may reduce inflammation and pain in arthritis or bursitis. For ganglion cysts, aspiration (fluid drainage with a needle) can be performed. If conservative measures fail, or if the bump causes significant pain or functional impairment, surgical options may be considered. Surgery might involve removing cysts, repairing damaged tendons, or addressing advanced arthritis damage.