Arthritis vs. Osteoarthritis: Differences, Types, Chart

Arthritis is a blanket term for over 100 types of diseases that affect the joints.

The terms arthritis and osteoarthritis are often confused.

• Arthritis is a broad term that refers to the inflammation (swelling and pain) of the joints. There are over 100 types of arthritis, and osteoarthritis is the most common type.
• Osteoarthritis is a specific type of arthritis in which there is wearing out of the joint cartilage (the firm and rubbery tissue that cushions and protects the end of the bones participating in joint formation).

4 types of arthritis

Arthritis is a blanket term for over 100 types of diseases that affect the joints. It is classified into various categories based on several factors such as the cause, underlying mechanism of joint damage, and age group they primarily affect.

Arthritis is broadly divided into four groups that include:

1. Degenerative arthritis: This is the most common type of arthritis. It occurs due to the wear and tear of the joint cartilage. Osteoarthritis falls into this category.
2. Inflammatory arthritis: This type of arthritis occurs when an overactive immune system mistakenly attacks the joints. This results in joint inflammation and consequent joint damage. Examples include rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis.
3. Infectious arthritis (septic arthritis): As the name suggests, infectious arthritis occurs due to joint infection and inflammation caused by bacteria, viruses, or fungi. Arthritis may be associated with signs of infection such as fever and chills. Appropriate medications against the causative microorganism are needed to treat this form of arthritis. Some of the microorganisms that cause infectious arthritis include shigella, salmonella, hepatitis C virus, gonorrhea, and chlamydia.
4. Metabolic arthritis: It occurs due to the buildup of a product of metabolism in the body called uric acid. Uric acid is produced from the breakdown of purines, which are substances naturally found in the body and consumed through some foods or drinks. The type of arthritis due to an excessive uric acid buildup in the joints is called gout.

Comparison between the main types of arthritis

Four major types of arthritis are compared in the table below:

Degenerative
Inflammatory
Metabolic
Inflammatory

• Degenerative disease in which there is wearing out of the joint cartilage

• A chronic inflammatory condition in which the body’s immune system attacks its joints and other tissues and organs

• Occurs due to increased blood levels of a substance called uric acid (hyperuricemia)

• A chronic inflammatory condition that causes damage to the joints

• The most common type of arthritis affecting over 32 million adults in the United States

• Affects about 1.5 million people in the United States

• Affects about 9 million people in the United States

• Affects about 1 million people (30 percent of people with psoriasis) in the United States

• Older age
• Obesity
• Joint injury or overuse
• A family history
• Female gender, especially postmenopausal women

• Female gender (two to three times higher risk of RA than men)
• Older age
• Smoking
• Genetic factors
• Obesity
• Parity (women who have never given birth are at an increased risk of RA)

• Purine-rich diet
• Obese
• Male gender
• Certain diseases such as kidney or heart disease, metabolic syndrome
• Certain medications
• A family history of gout
• Recent trauma or surgery

• Having psoriasis
• Having a family history of psoriasis or psoriatic arthritis
• Being 30 to 55 years of age
• Certain bacterial (such as Strep) or viral (such as human immunodeficiency syndrome) infections
• Following a joint injury in a person with psoriasis
• Being overweight or obese
• Smoking

• Joint pain and tenderness
• Swollen joints
• Grating or crunching sensation on using the joint
• Joint stiffness
• Morning stiffness less than 30 minutes
• Palpable bony swellings or spurs

• Joint pain involving one or more joints
• Joint swelling involving one or more joints
• Symmetric arthritis (joints on both sides of the body, such as both right and left-hand joints, affected)
• Joint stiffness particularly in the morning or after periods of rest or inactivity
• Extra-articular symptoms such as fever, fatigue, weight loss, dry eyes, dry mouth, involvement of other organs such as the skin, heart, lungs, kidney

• Severe joint pain that can affect any joint but typically occurs in the great toe
• Swollen, warm, and tender joints
• Stiffness or reduced range of motion
• Pain is generally most severe within the first 12 hours of its onset and then lasts for a week or two with no symptoms between flare-ups

• Painful and tender joints
• Asymmetric arthritis
• Joint swelling
• Joint stiffness particularly in the morning
• Fatigue
• Reduced range of motion
• Nail changes (such as pitted nails or separation of nails from the nail bed)
• Sausage-like swollen toes and fingers
• Eye pain or redness
• Blurred vision
• Low backache
• Skin rash
• Urogenital involvement (such as inflammation of the vagina, cervix, urethra, penis, or prostate gland)
• Involvement of other organs such as the heart, liver, and gut

• Medical history
• Physical examination
• Presence of characteristic degenerative changes on X-ray
• Other tests such as blood tests, and synovial fluid examination may be done to rule out other causes

• Medical history
• Physical examination
• Blood tests such as tests for autoantibodies such as rheumatoid factor and anti-CCP antibody.
• Inflammatory markers such as ESR and CRP, (liver function tests, kidney function tests)
• Imaging studies such as X-ray, computed tomography (CT) scan, and magnetic resonance imaging (MRI)
• Other tests such as echocardiography to look for heart involvement and pulmonary function tests to look for lung involvement

• Medical history
• Physical examination
• Blood tests to measure uric acid levels
• Imaging studies such as X-ray, ultrasound, CT scan, and MRI.
• Another specialized imaging test called dual-energy computerized tomography may be done to detect urate crystals in joint space
• Synovial fluid examination to look for uric acid crystals

• Medical history
• Physical examination
• Blood tests to exclude RA and other causes of arthritis. There may be increased levels of inflammatory markers such as ESR and CRP
• Imaging studies such as X-rays, CT scans, and MRI
• Synovial fluid examination (involves collecting joint fluid through a needle and examining the fluid under a microscope)

• Lifestyle modifications including exercise and weight management
• Pain medications
• Physical therapy 
• Supportive devices such as cane, walker, and shoe inserts
• Intraarticular steroid injections
• Surgery

• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Corticosteroids
• Disease-modifying antirheumatic drugs (DMARDs) such as sulfasalazine, methotrexate, and leflunomide
• Biological response modifiers or biologicals such as abatacept, adalimumab, and tocilizumab
• Janus kinase (JAK) inhibitors such as baricitinib, tofacitinib, and upadacitinib
• Physical therapy
• Surgery

• Dietary modifications
• NSAIDs
• Xanthine oxidase inhibitors such as allopurinol and febuxostat
• Colchicine
• Probenecid 
• Corticosteroids

• NSAIDs 
• DMARDs such as sulfasalazine, methotrexate and leflunomide
• Biological response modifiers or biologicals such as adalimumab, certolizumab, and etanercept
• JAK inhibitors such as tofacitinib
• Phosphodiesterase-4 inhibitors such as apremilast
• Physical therapy
• Intraarticular steroids
• Surgery