Arthritis describes over 100 different conditions that involve inflammation of any part of a joint, including the joint lining (synovium), cartilage, bones, and supporting tissues. Arthritis may affect one, a few, or many joints throughout the body.
The three most common types of arthritis include:
- Osteoarthritis
- The most common type of arthritis
- Frequently develops with age
- A chronic condition in which the cartilage between bones that cushions the joints wears down and as it does, the bones rub against each other causing pain, stiffness, swelling, and reduced joint motion
- Most commonly affects the hands, knees, hips, feet, and spine, though it can affect nearly any joint in the body
- Rheumatoid arthritis (RA)
- A chronic autoimmune disorder characterized by persistent joint pain, swelling, and stiffness
- Can also affect the skin, heart, lungs, and eyes
- Differs from some other forms of arthritis because it affects both sides of the body
- Psoriatic arthritis
- A type of inflammatory arthritis that may develop in people with psoriasis, a chronic autoimmune skin condition that causes fast skin cell growth and renewal
- Can affect any joint, but commonly occurs in large joints of the lower extremities such as the knees and ankles
Other types of arthritis include:
- Childhood arthritis
- Infectious arthritis
- Fibromyalgia
- Gout
- Systemic lupus erythematosus (SLE)
What Are Symptoms of Arthritis?
Joint symptoms are the main symptom of most types of arthritis. Certain types of arthritis affect the joints symmetrically (on both sides of the body). In some types of arthritis, pain is aggravated by movement and weight bearing and is relieved by rest.
Joint symptoms of arthritis include:
- Pain
- Stiffness
- Swelling
- Tenderness
- Redness
- Warmth
- Limited movement/decreased range of motion or flexibility
Depending on the type of arthritis, other symptoms that may accompany joint symptoms include:
- Weakness
- Weight loss
- Fever
- Fatigue/tiredness
- Headaches, including migraines
- Numbness or tingling in hands and feet
- Depression
- Anxiety
- Sleep problems
- Problems with thinking, memory, and concentration
- Pain in the face or jaw, including temporomandibular joint syndrome (TMJ)
- Digestive problems, such as abdominal pain, bloating, constipation, and irritable bowel syndrome (IBS)
What Causes Arthritis?
There are many possible causes of arthritis, such as:
- Age-related wear and tear
- Infections
- Autoimmune conditions
- Injuries
How Is Arthritis Diagnosed?
Arthritis is diagnosed with a medical history and physical examination, along with laboratory and imaging tests.
Tests used to diagnose arthritis include:
- Blood tests
- Rheumatoid factor (RF)
- Anti-cyclic citrullinated peptide (CCP)
- Antinuclear antibody (ANA) for SLE
- Arthrocentesis (also called joint aspiration or joint tap)
- Testing of synovial fluid inside the joint
- X-rays (also used to monitor changes in the joint over time)
- Magnetic resonance imaging (MRI)
- Computed tomography (CT) scan
- Ultrasound
What Is the Treatment for Arthritis?
Treatments for arthritis include:
- Physical and occupational therapy
- Pain relievers (such as acetaminophen)
- Anti-inflammatory medications (such as ibuprofen)
- Medications that suppress the immune system (such as prednisone or methotrexate)
- Antibiotics for bacterial joint infections
From 
https://www.uptodate.com/contents/arthritis-beyond-the-basics?search=Arthritis&source=search_result&selectedTitle=9~150&usage_type=default&display_rank=9
https://www.cdc.gov/arthritis/basics/types.html
https://www.arthritis.org/health-wellness/healthy-living/nutrition/foods-to-limit/8-food-ingredients-that-can-cause-inflammation