There are more than 100 different types of arthritis. The term arthritis is derived from the Greek, "arthron" meaning joint and "itis" meaning inflammation.
Despite the multiplicity of conditions encompassed by this term, there are some forms of arthritis which are much more common than others. Examples include osteoarthritis, rheumatoid arthritis, gout, pseudogout, and psoriatic arthritis (PA).
PA is a chronic, systemic, autoimmune-driven inflammatory form of arthritis that occurs with increased prevalence in patients who also have psoriasis, a skin condition. According to the National Psoriasis Foundation, between 10% and 30% of people with psoriasis develop PA.
Symptoms of this condition may be mild. However, many patients develop severe arthritis with pronounced stiffness, joint swelling, pain and limited range of motion. One distinguishing feature of this disease is the extensive involvement of the ligaments and tendons adjacent to joints. The tendon and ligament involvement may be quantitatively greater than the joint involvement.
The tendons that appear to be involved most often are the Achilles, patellar tendon of the knee, tendons of the elbow, and the tendons of the fingers and toes.
Patients with PA can develop painful swelling of the fingers and toes. The swelling can be so profound that the digits look like sausages. They are sometimes referred to as "sausage digits." An unusual, but devastating form of PA can cause mutilation deformity of the fingers.
Skin involvement with psoriasis is not usually difficult to spot although it is important to examine all areas where the rash can occur including the scalp, behind and in the ears, armpits, belly button, gluteal crease, and inguinal region.
The finger nails and toe nails may show tiny pits or actually seem to lift off the nail bed. These changes are sometimes misdiagnosed as being due to fungus.
Systemic symptoms and signs may be present. A large percent of patients with psoriatic arthritis develop inflammatory eye disease. Significant morning stiffness, lasting an hour or more, and fatigue are also features of this disease.
PA can also attack the axial skeleton- the spine.
Treatment of PA resides in making the proper diagnosis and initiating aggressive therapy. The diagnosis is suspected clinically and may be confirmed using imaging procedures such as magnetic resonance imaging (MRI).
Disease modifying anti-rheumatic drugs such as methotrexate and sulfasalazine can be helpful for the peripheral tendon and ligament inflammation. Usually though, patients require biologic therapy in order to obtain remission. Tumor necrosis inhibitors such as Enbrel, Humira, Remicade, and Simponi may be quite useful.