Seronegative arthritis is an umbrella term for various types of arthritis that have similar symptoms to rheumatoid arthritis but do not have the rheumatoid factor determining that condition in blood tests. Seronegative arthritis also tends to have additional symptoms that rheumatoid arthritis does not. Examples of these disorders include ankylosing spondylitis, psoriatic arthritis and reactive arthritis.
As with rheumatoid arthritis, the primary symptoms of seronegative arthritis include pain, inflammation and stiffness in the joints. This can occur in the hips, knees, ankles, feet, toes, shoulders, elbows, wrists, hands or fingers. Sometimes inflammation also occurs in the spine and at tendon attachment points. A flareup may involve only one side of the body.
The specific subtype of seronegative arthritis can be diagnosed more definitively by taking into account additional symptoms. These include acne and other skin lesions, canker sores, nail deformities, inflammatory bowel disease and inflamed eyes.
Psoriatic arthritis, for instance, occurs in up to 30 per cent of people with psoriasis, according to the National Psoriasis Foundation. In addition to pain and inflammation, nail deformities can occur, including pitting, thickening, yellowing and deterioration. People also may feel fatigued, and have red and sore tissues around their eyes. To make diagnosis even more complicated, psoriatic arthritis is itself an umbrella condition encompassing five types of psoriatic arthritis.
Another type of seronegative arthritis mainly affects the spine. This disorder is called ankylosing spondylitis, and usually begins with dull, chronic pain in the lower back and hips. The pain and stiffness eventually spread up the spine and into the neck, and may move further to ribs, shoulder blades, hips, thighs and heels. People also may feel fatigued, and have mild fever and anaemia. Many people with this disorder experience bowel inflammation and eye inflammation.
Reactive arthritis is often a temporary condition that is triggered by a bacterial infection. Joints in the knees, ankles and feet can become inflamed and swollen, and there also can be inflammation in the eyes and urinary tract. Skin rashes, nail disintegration and genital sores can occur. About 15 to 20 per cent of people with reactive arthritis will eventually develop a chronic form of the disorder, according to the Spondylitis Association of America.