Joint Swelling and Skin Lesions

🗒️ Question

A 42 year old woman presents to her GP with joint pain and swelling in her fingers, which started 6 months ago. She describes morning stiffness lasting over an hour and notes her symptoms improve with activity. She also reports patches of itchy, red skin on her elbows and knees. Her father has a history of psoriasis.

On examination, there is swelling of the proximal interphalangeal joints of both hands and onycholysis of several nails. Skin examination reveals well-demarcated erythematous plaques with silvery scaling on the elbows and knees.

Investigations

• CRP: 15 mg/L (<5)

• Rheumatoid factor: Negative

What is the most likely diagnosis?

(A) Osteoarthritis

(B) Psoriatic arthritis

(C) Rheumatoid arthritis

(D) Reactive arthritis

(E) Systemic lupus erythematosus