Why Do My Joints Hurt? Common Causes of Joint Pain

Joint pain is one of the most common reasons adults seek medical care. Whether it is a dull ache in your knees after climbing stairs, stiffness in your hands first thing in the morning, or sudden intense pain in your big toe that wakes you from sleep, joint pain can significantly impact your quality of life and daily function.

The challenge is that joint pain has dozens of potential causes—from simple overuse to serious autoimmune disease. Understanding the patterns of your pain, including which joints are affected, when pain occurs, and what makes it better or worse, provides important clues to the underlying cause and guides appropriate treatment.

Osteoarthritis: The Most Common Cause

Osteoarthritis (OA) is by far the most prevalent cause of joint pain, affecting over 32.5 million adults in the United States according to the CDC. Often called "wear-and-tear" arthritis, OA develops when the protective cartilage that cushions the ends of bones gradually breaks down over time.

OA most commonly affects weight-bearing joints including the knees, hips, and spine, as well as the joints of the hands—particularly the distal interphalangeal (DIP) joints at the fingertips and the base of the thumb. Characteristic features of osteoarthritis include pain that worsens with activity and improves with rest, brief morning stiffness lasting less than 30 minutes, a grinding or crepitus sensation during movement, gradual onset over months to years, and bony enlargements at the affected joints.

Risk factors for OA include advancing age (most common after age 50), obesity (excess weight increases joint stress), previous joint injury, repetitive occupational stress, family history, and female sex (women are affected more frequently after menopause).

Autoimmune and Inflammatory Arthritis

Unlike osteoarthritis, inflammatory arthritis results from the immune system attacking the body's own joint tissues. These conditions tend to affect younger patients and have distinctive clinical patterns.

Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune condition affecting about 1.3 million Americans. It characteristically causes symmetric joint involvement—the same joints on both sides of the body—with a predilection for the small joints of the hands and feet. Key features include prolonged morning stiffness lasting more than 30 to 60 minutes, joint swelling that is soft and boggy (rather than bony), fatigue and systemic malaise, and potential involvement of other organ systems. Early diagnosis and treatment of RA is critical, as joint damage can begin within months of symptom onset.

Psoriatic Arthritis

Psoriatic arthritis affects about 30% of individuals with psoriasis and can develop before, during, or after skin symptoms appear. It may present as asymmetric arthritis, involvement of entire digits (dactylitis or "sausage fingers"), enthesitis (inflammation where tendons attach to bone), and nail changes such as pitting or separation from the nail bed.

Ankylosing Spondylitis

This inflammatory condition primarily affects the spine and sacroiliac joints. It typically presents in young adults (under age 40) with chronic low back pain and stiffness that improves with exercise but worsens with rest—the opposite pattern of mechanical back pain.

Gout: Sudden, Intense Joint Pain

Gout is a form of inflammatory arthritis caused by the deposition of monosodium urate crystals in joints and surrounding tissues. It results from elevated levels of uric acid in the blood (hyperuricemia), which can crystallize in cooler, peripheral joints.

The classic gout attack is among the most painful conditions in medicine. It typically presents with explosive onset of severe pain, often beginning at night, extreme sensitivity—even the weight of a bedsheet can be unbearable, intense redness, swelling, and warmth of the affected joint, and a predilection for the first metatarsophalangeal joint (base of the big toe), though it can affect any joint.

Gout attacks are often triggered by dietary factors (red meat, shellfish, alcohol—particularly beer), dehydration, acute illness, certain medications (thiazide diuretics, low-dose aspirin), and surgical or physiologic stress. Without treatment, acute gout typically resolves within 7 to 14 days, but untreated gout tends to recur with increasing frequency and can cause permanent joint damage over time.

Viral Arthralgia: Joint Pain from Infection

Many viral infections cause transient joint pain (arthralgia) or joint inflammation (arthritis) as part of the immune response. This is an underrecognized cause of joint pain that often brings patients to medical attention.

Common viral causes of joint pain include influenza (joint and muscle aches are hallmark symptoms), COVID-19 (both during acute infection and as part of post-COVID syndrome), parvovirus B19 (particularly causes symmetric small joint arthritis mimicking RA in adults), hepatitis B (joint pain may precede jaundice by weeks), chikungunya and dengue (associated with severe polyarthralgia), and Epstein-Barr virus (mononucleosis).

Viral arthralgia typically affects multiple joints simultaneously, occurs during or shortly after the acute illness phase, and resolves within 2 to 6 weeks. However, some patients—particularly those with parvovirus or chikungunya—may experience persistent joint symptoms for months. Post-COVID joint pain has been reported in a significant percentage of long COVID patients.

Overuse Injuries and Tendinitis

Repetitive strain on joints and their supporting structures is a frequent cause of pain that is often attributed to "the joint" but actually originates from surrounding tendons, bursae, or ligaments.

Tendinitis and Tendinopathy

Tendinitis refers to inflammation of a tendon, typically from repetitive use. Common presentations include lateral epicondylitis (tennis elbow), medial epicondylitis (golfer's elbow), rotator cuff tendinitis (shoulder pain with overhead activity), patellar tendinitis (pain below the kneecap with jumping or stairs), and Achilles tendinitis (posterior ankle pain). Pain from tendinitis is typically activity-related, localizable to a specific point, and reproducible with specific movements that stress the affected tendon.

Bursitis

Bursae are fluid-filled sacs that reduce friction between tissues. When inflamed (bursitis), they cause localized pain, swelling, and tenderness. Common sites include the shoulder (subacromial bursitis), hip (trochanteric bursitis—a very common cause of lateral hip pain), knee (prepatellar bursitis), and elbow (olecranon bursitis).

Other Important Causes of Joint Pain

Lyme Disease

In endemic areas (including Maryland and Delaware), Lyme disease transmitted by deer ticks can cause joint pain—particularly affecting the knee—weeks to months after the initial tick bite. Joint involvement in Lyme disease often presents as intermittent episodes of joint swelling, most commonly monoarticular (one joint at a time).

Fibromyalgia

While not a joint disease per se, fibromyalgia causes widespread musculoskeletal pain that patients often localize to their joints. It is characterized by diffuse pain, fatigue, sleep disturbance, and cognitive difficulties ("fibro fog"). Physical examination reveals tender points but no actual joint swelling or inflammation.

Hypothyroidism

Underactive thyroid function can cause joint pain, stiffness, and swelling that mimics inflammatory arthritis. This is an important and treatable cause to rule out, particularly in women.

Diagnostic Approach to Joint Pain

When evaluating joint pain, healthcare providers consider several key questions: Is the pain in one joint (monoarticular) or multiple joints (polyarticular)? Is there true joint swelling or just pain? Are symptoms symmetric or asymmetric? How long has pain been present (acute vs. chronic)? Is there morning stiffness, and how long does it last? Are there associated systemic symptoms like fever, rash, or fatigue?

Based on clinical assessment, appropriate testing may include blood work (inflammatory markers like ESR and CRP, rheumatoid factor, anti-CCP antibodies, uric acid, ANA, Lyme titers, thyroid function), imaging (X-rays, ultrasound, or MRI), and occasionally joint aspiration (arthrocentesis) to examine synovial fluid.

Initial Management Strategies

While specific treatment depends on the underlying diagnosis, several strategies provide symptomatic relief for most types of joint pain. Activity modification—not complete rest—is generally recommended. Maintaining gentle movement helps preserve range of motion and prevents deconditioning, while avoiding activities that provoke severe pain allows healing.

Over-the-counter anti-inflammatory medications (NSAIDs) such as ibuprofen and naproxen provide pain relief for many causes of joint pain. Acetaminophen may be appropriate for those who cannot take NSAIDs. Topical anti-inflammatory agents (diclofenac gel) can be effective for superficial joints like knees and hands with fewer systemic side effects.

Physical therapy and targeted exercise programs have strong evidence for osteoarthritis management, often providing comparable pain relief to oral medications. Weight management reduces mechanical stress on joints—every pound of body weight lost reduces knee joint load by about four pounds.

Frequently Asked Questions