Psoriatic Arthropathy

In station 5 you may be asked to assess a patient with joint pains.

HISTORY (3 minutes):

  • Timing questions (sudden/gradual, since when, intermittent/constant, progression, previous episodes)
  • Pattern of joint involvement (which joints, uni/bilateral, order they became affected in, large/small joints, back/neck pain)
  • Joint pain/swelling/stiffness in the morning (how long for)/redness/deformity/nodules
  • Function
  • Extraarticular features of PsA:
    • Nail changes and psoriasis
    • Red/painful eye
    • Plantar fasciitis, Achilles tendonitis, dactylitis (ever had a swollen finger/toe)
    • Spondylitis specific questions if patient indicates back pain:
      • When is back pain worst? Morning?
      • Does exercise help?
      • Stiff in morning? How long for?
      • Do you wake in the night?
      • Pain in buttock?
      • Neck pain?
    • Extraarticular features of RA:
      • Systemic upset: fever, night sweats, weight loss, fatigue, lymph nodes
      • Raynauds
      • Skin, nails, hair: rashes, photosensitivity, hair loss, ulcers
      • Eyes: dry/red/painful/change in vision
      • CVS/Resp/GI/Neuro systems review
    • PMH joint disease/psoriasis/IBD/autoimmune conditions
    • Fx as above
    • Dx treatments tried including NSAIDs
    • Sx including impact

EXAMINE (3 minutes)

  • Hand dorsum
    • Swellings of MCP, PIP, wrist, redness, guttering of interossei, deformities (subluxation and ulnar deviation at MCPJs, subluxation of wrist, swan neck, Boutonnieres, z thumb deformities in RA/ RA-type PsA), nails (psoriasis, infarcts, vasculitis), thin and bruised skin (steroids), scars (carpal tunnel release, wrist arthrodesis, tendon transfer etc), rashes (psoriasis), dactylitis (psoriatic arthritis)
  • Hand palm
    • Palmer erythema, muscle wasting, scars
  • Elbow
    • Nodules, psoriatic plaques, gouty tophi, scars, bursitis
  • Feel
    • Palpate MCPJs, PIPJs, wrist for tenderness, swelling, temperature
    • Feel the pulse
    • Carpal tunnel tests if indicated (sensation, power, Tinel’s and Phalen’s tests)
    • Feel over the elbows
  • Move
    • Ask to straighten fingers fully
    • Ask to do prayer sign
    • Ask to make a fist and hide your nails
    • Grip my fingers and squeeze
    • Pincer grip (make an O and don’t let me open it)
    • Assess function eg. do a button, write, pick up a coin/glass.
    • Put both hands behind your head
    • Assess elbow and shoulder function if time allows as well as lower limb joints
  • Look behind the ears and in the hair line and scalp for psoriasis
  • Inspect the back from front, side, behind. Observe stooped question mark posture (loss of L lourdosis and fixed kyphosis with hyperextensions of C spine to maintain horizontal gaze)
  • Palpate the spine- processes, muscles, SIJ
  • Assess range of movement of the neck and back ROM
  • Offer to perform Shobers test and assess the occiput-wall distance
  • Look at the eyes: redness, conjunctival pallor
  • Chest expansion, check for pacemaker, feel apex beat
  • Listen for AR murmur, listen for apical creps
  • Look at the abdomen for psoriasis around umbilicus
  • Look at the feet- tendonitis, dactylitis
  • Neuro- assess power, sensation, plantars if back pain



ICE and Explanation (2 minutes)



Present to the examiner:

“This lady has a peripheral assymetrical deforming polyarthropathy.  There is (no) active synovitis.  The presence of psoriatic plaques and nail changes, dactylitis and enthesitis suggests psoriatic arthropathy.  Hand function was preserved/limited. “


5-10% with psoriasis get PsA.  Psoriasis precedes PsA by 8-10 years in 70%

PsA occurs simultaneously/precedes psoriasis in 30%

40% have a positive family history

Affects most often 35-50 year old males and females

Skin and joints can flare simultaneously/separately

Joint disease is most often peripheral (95%, synovitis, tenosynovitis, enthesitis). It can be axial only (5%). Patients can get a mixture of peripheral and axial disease


CASPAR criteria to diagnose (≥ 3 points):

  1. Psoriasis (current, past, Fx)
  2. Psoriatic nail dystrophy
  3. Negative Rheumatoid factor
  4. Dactylitis (current or past)
  5. XRay: juxtaarticular new bone formation


Subtypes (Moll and Wright 1973):

Assymetrical oligoarthritis     15-20%            DIPJs+PIPJs, MCPJs+MTPJs, knee+hip, dactylitis

Predominantly DIPJ                 2-5%                Nail changes

Arthritis mutilans                    5%                   Telescoping

RA-like                                     50-60%            Wrist involvement

Axial (only)                              2-5%                Assymetrical sacroilitis


Think PsA (rather than RA) if:

  • Assymetrical joint disease
  • Rheumatoid Factor negative
  • Psoriatic nail changes
  • DIPJ involvement (and not osteoarthritis)
  • Dactylitis, enthesitis
  • Fx psoriasis/PsA


Extraarticular features of PsA:

  • Nail involvement (80%)- pitting, ridging, onycholysis, hyperkeratosis
  • Ocular involvement (conjunctivitis, iritis)

Differential Diagnoses: RA, other seronegative spondylarthritides (Ankylosing spondylitis, IBD arthritis, Reactive arthritis), OA, crystal arthritis (gout/pseudogout)



RF and anti-CCP (usually negative)

ANA (usually negative)

ESR/CRP (normal or increased)

FBC (anaemia), U+E (NSAIDs), LFT (pre-immunosupression)

Urine dipstick

HLA-B27 testing if sacroilitis

Joint aspirate: raised WCC, no culture/crystals

XRay: assymetrical changes, no periarticular osteopenia, DIPJ involvement, erosion of terminal tufts, pencil in cup deformity, sacroilitis, juxtaarticular new bone formation



Lifestyle advice: weight loss, exercise, smoking


Steroid injection of joints/ligaments/tendons. Careful with steroids (risk skin flare!)

DMARD when NSAIDs fail, 3+ joints involved/PASI score>10 (methotrexate, sulfasalasine, leflunomide)

Anti-TNF agents

Ustekinumab (IL-23, IL-12 inhibitor)

Apremilast (PDE4 inhibitor)

Surgical: joint replacement

Dermatology opinion on skin disease (see “Station 5 Psoriasis and Eczema)



Written by Dr Sarah Kennedy


Resources used to write this document include those listed in the references section of this webpage and also:


Rheumatology Secrets by Sterling West