Diagnosing arthritis of the fingers can be difficult. Arthritis can affect any joint in the body, but it is commonly seen in the joints of the fingers. These are the different types of arthritis and the pattern of joint involvement:
- Generalized Osteoarthritis
- Psoriasis
- Gout
- Juvenile Rheumatoid Arthritis
With Generalized Osteoarthritis, nodes are commonly seen. Heberden’s nodes are hard or bony swellings that can develop in the distal interphalangeal joints (DIP) and may or not be painful. Heberden’s nodes are caused by the formation of the osteophytes due to repeated trauma at the joint and usually occurs during middle age. Bouchard’s nodes are bony growths that can form on the proximal interphalangeal joints of the finger (PIP). Bouchard’s nodes, like Heberden’s nodes, may or may not be painful. Bouchard’s nodes are typically associated with limited motion of the affected joint. Mucous Cysts are small, fluid-filled sacs that form between the DIP joint of the finger and the bottom of the fingernail. The best treatment for a mucous cyst is a surgical excision of the cyst and removal of the underlying osteophyte to decrease the risk of recurrence.
Psoriasis is an inflammatory form of arthritis and is sometimes confused with osteoarthritis. Dactylitis is also referred to as “sausage digit” and is the inflammation of the entire digit. Sausage fingers is a major finding of psoriatic arthritis. Nail pitting are small depressions in the finger nails and are common in people who have psoriasis.
Gout is a form of inflammatory arthritis that is sometimes called “gouty arthritis”. Gouty arthritis will mimic infection and may develop in people who have high levels of uric acid in the blood. The uric acid can form needle-like crystals in the joint and cause pain, tenderness, swelling, and tenosynovitis. Periarticular erosions seen on an x-ray may also be present with gout of the finger joints. Periarticular erosions are usually multiple and bilateral with sclerotic borders.
In Juvenile Rheumatoid Arthritis, patients are antinuclear antibody (ANA) positive 30% of the time. The rheumatoid factor is negative in a child, but may become positive later in life. The patient may have shortened digits. Polyarticular rheumatoid arthritis (JRA) is a form of juvenile rheumatoid arthritis that affects five or more joints. Polyarticular occurs in about 30% of cases of JRA. Pauciarticular onset juvenile idiopathic arthritis (JIA) is a form of juvenile rheumatoid arthritis that affects less than five joints, and occurs in about 50% of cases of juvenile arthritis. In pauciarticular onset juvenile idiopathic arthritis, the physician should check the iris of the eye for iridocyclitis.
