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A. Characteristicsnavigator

  1. Peak age onset of psoriasis 5-15 years but PA peaks later
  2. ~6% change pattern of presentation
  3. Association With Psoriasis
    1. 75% develop skin disease (psoriasis) prior to arthritis
    2. 10% develop arthritis first
    3. 15% show concommitant development of psoriasis and arthritis
  4. HLA-B27 in ~45% of cases
  5. Cervical spine involvement more frequent if severe scalp psoriasis
  6. Enthesopathy (pain on tendon insertions onto bone) in PA
    1. Particularly at insertion of achilles into calcaneum
    2. Plantar fasciitis also occurs
    3. Musculotendinous insertions around pelvis may also be painful
  7. Ocular involvement in 1/3 of PA patients
    1. Conjunctivitis 20%
    2. Iritis 7%
  8. HIV infection tends to increase flares, more severe disease

B. Classification by Moll and Wright navigator

  1. Arthritis may have several distinct patters
  2. Classically, confined to distinal interphalangeal joint
    1. Usually severe
    2. Usually with nail pitting
  3. Symmetric Polyarthritis
    1. Often indistinguishable from Rheumatoid Arthritis (RA)
    2. DIP involvement always associated with psoriatic nails
  4. Asymmetric Pauciarticular
    1. Small joints and sausage digits
    2. Oligoarthtitis usually knee +/- IP/dactylitis
  5. Ankylosing spondylitis
    1. May occur with peripheral arthritis
    2. Asymptomatic sacroiliitis in 1/3 psoriasis cases
  6. Arthritis mutilans with sacroiliitis
  7. All forms are nearly always rheumatoid factor (RF) negative

D. Juvenille Psoriatic Arthritisnavigator

  1. Pattern
    1. Usually asymmetric polyarthritis
    2. Pauciarticular and spondylitis also occur
  2. Presentation
    1. ~50% arthritis first
    2. ~40% psoriasis first
    3. Remainder have simultaneous onset of disease

E. Radiographsnavigator

  1. Spine
    1. Asymmetric sacroiliitis
    2. Fluffy hyperostosis of vertebrae
  2. Periphery
    1. Asymmetric small joints, interphalgeal
    2. Marginal erosion with adjacent proliferation and whiskering
    3. Osteolysis of phalangeal and metacarpal bones - telescoping digits
    4. Pencil cup deformities
    5. Periostitis
    6. Hyperostosis

F. Differential Diagnosis navigator

  1. Rheumatoid Arthritis
  2. Reactive arthritis and Reiter's Syndrome
  3. Enteropathy (inflammatory bowel disease) Associated Arthropathy
  4. HIV Arthropathy

G. Treatment navigator

  1. NSAIDs
    1. Usually requires at least 1 month for improvement
    2. High doses usually required
    3. Indomethacin has been recommended first line but cannot be used chronically
    4. Newer COX-2 selective agents celecoxib or rofecoxib may be used chronically
  2. Methotrexate (Rheumatrex®)
    1. Agent of choice for moderate to severe disease
    2. Begin at 7.5mg q week but 15-30mg per week are usually required
    3. Intramuscular or sc injections may be more effective
    4. This agent also treats skin disease well
  3. Etanercept (Enbrel®) [3]
    1. Soluble tumor necrosis factor alpha receptor (TNF-R); blocks TNFa functions
    2. In 12 week study, provided substantial benefits to 87% of psoriatic arthritis patients
    3. Substantial improvement in joint symptoms as well as skin disease
    4. Well tolerated therapy; may be used in combination with methotrexate
    5. Dose was 25mg subcutaneously twice weekly
    6. Other TNFa blockers also active in psoriatic skin and joint disease [2]
  4. Sulfasalazine
    1. Appears to be effective in mild to moderate disease [4]
    2. Gradually increase dose to 3000mg / day, divided (bid or tid)
    3. Olsalazine may be tried in patients with sulfa allergies
  5. Prednisone
    1. Will improve arthritis
    2. Tapering prednisone usually causes skin disease flares
    3. This agent is generally avoided because of the skin flares
    4. However, steroids may be safest therapy in patients with HIV infection and psoriasis
  6. Cyclosporine
    1. Low to moderate doses (2-4mg/kg/day) are generally very effective
    2. Strongly consider use in patients unresponsive or toxic with methotrexate
    3. May be used in HIV+ patients with improvement in skin and joint disease [5]

References navigator

  1. Khan MA. 2002. Ann Intern Med. 136(12):896 abstract
  2. Schon MP and Boehncke WH. 2005. NEJM. 352(18):1899 abstract
  3. Mease PJ, Goffe BS, Metz J, et al. 2000. Lancet. 356(9227):385 abstract
  4. Gupta AK, Grober JS, Hamilton TA. 1995. J Rheum. 22(5):894 abstract
  5. Tourne L, Durez P, Van Vooren JP, et al. 1997. J Am Acad Dermatol. 37(3 Pt 1):501 abstract