This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Arthritis, Subject name: Orthopaedics
Distal interphalange of joint is commonly involved in: 
Select and explain. 
A. Gouty arthritis, B. Psoriatic arthritis, C. Reactive arthritis, D. Rheumatoid arthritis
B: Psoriatic arthritis
Answer: B: Psoriatic arthritis 
Explanation: (Psoriatic arthritis): Ref: 247 - M, 64-A* The important distinguishing features of psoriatic arthritis are:1. Asymmetrical joint distribution2. Involvement distal finger joints3. The presence of sacroilitis or spondylitis4. The absence of rheumatoid nodule* Osteoarthritis: - Knobbly appearance of distal inter phalagcal joint (Herberden's nodes) and less often the proximal interphalangeal joints (Bouchard's nodes)* SLE: - The joint involvement is not symmetrical nor are ankylosis and erosions common* Rheumatoid arthritis: - Bilateral symmetrical polyarthritis involving the proximal joints of the hands or feet the joints affected most commonly are the metacarpophalangeal joint s particularly that of the index fingers.