August is Psoriasis Awareness month. Psoriasis is a skin disease but it can also lead to a type of arthritis called psoriatic arthritis. As with rheumatoid arthritis psoriatic arthritis causes inflammation and pain in the joints, can can cause disability.
Here are some posts regarding psoriasis:

Efalizumab for Psoriasis May Trigger Psoriatic Arthritis
Press Release: FDA Committee Unanimously Recommends Approval of Ustekinumab for Plaque Psoriasis
Press release: New Guidelines for the Management of Psoriasis and Psoriatic Arthritis
Biologic agents for treatment of psoriasis
Press release: Ustekinumab Phase 3 data show long-term improvement of chronic plaque psoriasis
Press release: Humira (adalimumab) Receives FDA Approval For Moderate to Severe …read more

According to a study published in the June issue of Arthritis and Rheumatism, the medication efalizumab, which is used to treat moderate-to-severe psoriasis, may bring on a type of arthritis called psoriatic arthritis.
In an evaluation of 16 patients who were receiving efalizumab when they developed psoriatric arthritis, the researchers found that 8 had arthritis in the peripheral joints (fingers, toes), 7 had arthritis in joints throughout the body, and 1 had arthritis in the spine.
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