While the auto-immune condition rheumatoid arthritis is common in us, it remains rare in pets, occurring mainly in the foot joints (carpal and tarsal joints) in toy or small breeds from approximately one to eight years old. (Many pet owners tell us their pets are "rheumatic" or have "rheumatism". We know what you mean but to be more accurate, these pets are "arthritic".) Rheumatoid arthritic pets are uncomfortable, may have a fever and eat less. In early stages of rheumatoid arthritis there may be enlargement of lymph nodes.
More common is a non-deforming auto-immune arthritis, usually seen in purebred dogs, causing intermittent cycles of fever, lethargy and lameness involving more than one joint.
Diagnosis and treatment
Both rheumatoid arthritis and non-deforming arthritis are difficult to diagnose. An elevated blood "rheumatoid factor" is not sufficient. Other blood tests are also used. Treatment is as frustrating as diagnosis. Corticosteroids give only temporary relief. We often use more potent immune suppressing drugs.