Psoriatic Arthritis

Question 1

What is it part of?

What is it?

Answer 1

It is part of the “seronegative spondyloarthropathy” group of conditions

inflammatory arthritis associated with psoriasis

Question 2

Types

Answer 2

1. Symmetrical polyarthritis presents similarly to rheumatoid arthritis and is more common in women
   - hands, wrists, ankles and DIP joints are affected
   - MCP joints are less commonly affected (unlike rheumatoid).
2. Asymmetrical oligoarthritis affecting mainly the digits (fingers and toes) and feet: osteoarthritis like
3. Spondylitic pattern is more common in men. It presents with:
   - Back stiffness
   - Sacroiliitis
   - Atlanto-axial joint involvement
4. Arthritis mutilans (severe deformity fingers/hand, ‘telescoping fingers’)

Question 3

Clinical Features

Answer 3

Plaques of psoriasis on the skin

Pitting of the nails

Onycholysis (separation of the nail from the nail bed)

Dactylitis (inflammation of the full finger)

Enthesitis (inflammation of the entheses, which are the points of insertion of tendons into bone)

Question 4

Systemic complications

Answer 4

Eye disease (conjunctivitis and anterior uveitis)
Aortitis (inflammation of the aorta)
Amyloidosis

Question 5

X ray findings

Answer 5

• Periostitis is inflammation of the periosteum causing a thickened and irregular outline of the bone
• Ankylosis is where bones joining together causing joint stiffening
• Osteolysis is destruction of bone
• Dactylitis is inflammation of the whole digit and appears on the xray as soft tissue swelling
• Pencil-in-cup appearance: central erosions of the bone beside the joints and this causes the appearance of one bone in the joint being hollow and looking like a cup whilst the other is narrow and sits in the cup

Question 6

Management

What is contraindicated?

Answer 6

There is a crossover between the systemic treatments of psoriasis and treatment of psoriatic arthritis. Treatment is often coordinated between dermatologists and rheumatologists.

Depending on the severity the patient might require:

• NSAIDs for pain
• DMARDS (methotrexate, leflunomide or sulfasalazine)
• Anti-TNF medications (etanercept, infliximab or adalimumab)

Hydroxychloroquine is contraindicated due to triggering psoriasis