eMedicine Specialties > Physical Medicine and Rehabilitation > Arthritis & Connective Tissue Disorders

Psoriatic Arthritis: Differential Diagnoses & Workup

Author: Michael F Saulino, MD, PhD, Assistant Professor, Department of Physical Medicine and Rehabilitation, Thomas Jefferson University, MossRehab
Coauthor(s): Jeffrey M Heftler, MD, Interventional Physiatrist, Orthopaedic and Neurosurgical Specialists, Greenwich, CT
Contributor Information and Disclosures

Updated: Mar 24, 2009

Differential Diagnoses

Rheumatoid Arthritis

Other Problems to Be Considered

Lupus erythematosus: This condition can produce a rash similar to a psoriatic rash. Usually, the arthritis associated with lupus is not as deforming as that associated with psoriasis arthritis
Rheumatoid arthritis
Secondary syphilis: This can cause rash similar to a psoriatic rash. An arthropathy can be associated with syphilis, but this entity occurs years after the skin lesions have cleared in an untreated patient.
Ankylosing spondylitis: This condition can produce back pain similar to that associated with PsA but without the associated peripheral arthropathy or skin lesion.

Workup

Laboratory Studies

  • No laboratory studies can confirm the presence of psoriatic arthritis (PsA).7
  • HLA testing can assist in the prognosis of disease progression.2,5
  • Nonspecific elevation of the erythrocyte sedimentation rate may occur. Elevated serum uric acid levels have been observed in 10-20% of patients, especially those with severe skin disease.
  • Rheumatoid factor (RF) findings may be positive in up to 13% of PsA patients. Testing for RF can aid in diagnostic considerations, but it does not definitively differentiate PsA from rheumatoid arthritis.
  • Synovial fluid analysis typically reveals inflammatory cells with an increased number of neutrophils, usually 2,000-15,000/µL. Much higher counts can be seen in persons with larger effusions.

Imaging Studies

  • Radiography - This shows a combination of erosion (unlike in ankylosing spondylosis) and bone growth (unlike in rheumatoid arthritis [RA]) in affected joints.8 The following changes may be seen:
    • Pencil-in-cup deformity: This is tapering of the proximal phalanx as a result of bony erosion and bone growth in the distal phalanx. (See image below and Image 5.)
Arthritis mutilans (ie, "pencil-in-cup" deformiti...

Arthritis mutilans (ie, "pencil-in-cup" deformities).

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Arthritis mutilans (ie, "pencil-in-cup" deformiti...

Arthritis mutilans (ie, "pencil-in-cup" deformities).


    • Joint-space narrowing in the interphalangeal joints, possibly with ankylosis
    • Increased joint space in the interphalangeal joints as a result of destruction
    • Fluffy periostitis
    • Bilateral asymmetrical fusiform soft tissue swelling
    • Unilateral or symmetrical sacroiliitis
    • Large, nonmarginal, unilateral, asymmetrical syndesmophytes (intervertebral bony bridges) in the cervical, thoracic, and lumbar spine, often sparing some of the segments (See image below and Image 9.)


Lateral radiograph of the cervical spine shows sy...

Lateral radiograph of the cervical spine shows syndesmophytes at the C2-3 and C6-7 levels, with zygapophyseal joint fusion. Courtesy of Bruce M. Rothschild, MD.

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Lateral radiograph of the cervical spine shows sy...

Lateral radiograph of the cervical spine shows syndesmophytes at the C2-3 and C6-7 levels, with zygapophyseal joint fusion. Courtesy of Bruce M. Rothschild, MD.

  • Computed tomography (CT) scanning or magnetic resonance imaging (MRI) of the joints
    • These imaging tests may be useful for detecting early signs of joint synovitis.
    • MRI is particularly sensitive for detecting sacroiliitic synovitis, enthesis, and erosions; it can also be used with gadolinium to increase the sensitivity.
    • MRI may show inflammation in the small joints of the hands, involving the collateral ligaments and soft tissues around the joint capsule, a finding not found in persons with RA.
  • Ultrasonography - This has a somewhat undefined but emerging role in the diagnosis and management of psoriatic arthritis, including the ability to differentiate synovitis and enthesitis, accurately and objectively monitor disease activity, and accurately deliver local therapy.

Histologic Findings

Histologic findings from patients with psoriatic arthritis are similar to those found in patients with rheumatoid arthritis. They reveal synovium hyperplasia, polymorphonuclear infiltration early in the disease, and then mononuclear cells later, with cartilage erosion and pannus formation.

More on Psoriatic Arthritis

Overview: Psoriatic Arthritis
Differential Diagnoses & Workup: Psoriatic Arthritis
Treatment & Medication: Psoriatic Arthritis
Follow-up: Psoriatic Arthritis
Multimedia: Psoriatic Arthritis
References
Further Reading
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References

  1. Guttman-Yassky E, Krueger JG. Psoriasis: evolution of pathogenic concepts and new therapies through phases of translational research. Br J Dermatol. Dec 2007;157(6):1103-15. [Medline].

  2. Fitzgerald O, Winchester R. Psoriatic arthritis: from pathogenesis to therapy. Arthritis Res Ther. Feb 12 2009;11(1):214. [Medline].

  3. Gladman DD. Psoriatic arthritis. Dermatol Ther. Jan-Feb 2009;22(1):40-55. [Medline].

  4. [Best Evidence] Wilson FC, Icen M, Crowson CS, et al. Incidence and clinical predictors of psoriatic arthritis in patients with psoriasis: a population-based study. Arthritis Rheum. Feb 15 2009;61(2):233-9. [Medline].

  5. Nograles KE, Brasington RD, Bowcock AM. New insights into the pathogenesis and genetics of psoriatic arthritis. Nat Clin Pract Rheumatol. Feb 2009;5(2):83-91. [Medline].

  6. Duffin KC, Chandran V, Gladman DD, et al. Genetics of psoriasis and psoriatic arthritis: update and future direction. J Rheumatol. Jul 2008;35(7):1449-53. [Medline].

  7. Qureshi AA, Dominguez P, Duffin KC, et al. Psoriatic arthritis screening tools. J Rheumatol. Jul 2008;35(7):1423-5. [Medline].

  8. Siannis F, Farewell VT, Cook RJ, et al. Clinical and radiological damage in psoriatic arthritis. Ann Rheum Dis. Apr 2006;65(4):478-81. [Medline].

  9. [Best Evidence] Saad AA, Symmons DP, Noyce PR, et al. Risks and benefits of tumor necrosis factor-alpha inhibitors in the management of psoriatic arthritis: systematic review and metaanalysis of randomized controlled trials. J Rheumatol. May 2008;35(5):883-90. [Medline].

  10. Gelfand JM, Gladman DD, Mease PJ, et al. Epidemiology of psoriatic arthritis in the population of the United States. J Am Acad Dermatol. Oct 2005;53(4):573. [Medline].

  11. Gladman DD, Antoni C, Mease P, Clegg DO, Nash P. Psoriatic arthritis: epidemiology, clinical features, course, and outcome. Ann Rheum Dis. Mar 2005;64 Suppl 2:ii14-7. [Medline].

  12. Kane D. The role of ultrasound in the diagnosis and management of psoriatic arthritis. Curr Rheumatol Rep. Aug 2005;7(4):319-24. [Medline].

  13. Krueger JG, Bowcock A. Psoriasis pathophysiology: current concepts of pathogenesis. Ann Rheum Dis. Mar 2005;64 Suppl 2:ii30-6. [Medline].

  14. Kyle S, Chandler D, Griffiths CE, Helliwell P, Lewis J, McInnes I, et al. Guideline for anti-TNF-alpha therapy in psoriatic arthritis. Rheumatology (Oxford). Mar 2005;44(3):390-7. [Medline].

  15. Levine N. Scaly red plaques on dorsal part of hand. Patient notes morning stiffness and pain. Geriatrics. Dec 2005;60(12):17. [Medline].

  16. Nash P, Clegg DO. Psoriatic arthritis therapy: NSAIDs and traditional DMARDs. Ann Rheum Dis. Mar 2005;64 Suppl 2:ii74-7. [Medline].

  17. Salaffi F, De Angelis R, Grassi W. Prevalence of musculoskeletal conditions in an Italian population sample: results of a regional community-based study. I. The MAPPING study. Clin Exp Rheumatol. Nov-Dec 2005;23(6):819-28. [Medline].

  18. Shbeeb M, Uramoto KM, Gibson LE, O'Fallon WM, Gabriel SE. The epidemiology of psoriatic arthritis in Olmsted County, Minnesota, USA, 1982-1991. J Rheumatol. May 2000;27(5):1247-50. [Medline].

  19. Taylor WJ. Understanding psoriatic arthritis. Hosp Med. Mar 2005;66(3):163-7. [Medline].

  20. Taylor WJ, Zmierczak HG, Helliwell PS. Problems with the definition of axial and peripheral disease patterns in psoriatic arthritis. J Rheumatol. Jun 2005;32(6):974-7. [Medline].

  21. Winterfield LS, Menter A, Gordon K, Gottlieb A. Psoriasis treatment: current and emerging directed therapies. Ann Rheum Dis. Mar 2005;64 Suppl 2:ii87-90; discussion ii91-2. [Medline].

  22. Zangger P, Esufali ZH, Gladman DD, Bogoch ER. Type and outcome of reconstructive surgery for different patterns of psoriatic arthritis. J Rheumatol. Apr 2000;27(4):967-74. [Medline].

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Contributor Information and Disclosures

Author

Michael F Saulino, MD, PhD, Assistant Professor, Department of Physical Medicine and Rehabilitation, Thomas Jefferson University, MossRehab
Michael F Saulino, MD, PhD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, Association of Academic Physiatrists, and Physiatric Association of Spine, Sports and Occupational Rehabilitation
Disclosure: Nothing to disclose.

Coauthor(s)

Jeffrey M Heftler, MD, Interventional Physiatrist, Orthopaedic and Neurosurgical Specialists, Greenwich, CT
Jeffrey M Heftler, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation and American Medical Association
Disclosure: Nothing to disclose.

Medical Editor

Rajesh R Yadav, MD, Assistant Professor, Section of Physical Medicine and Rehabilitation, MD Anderson Cancer Center, University of Texas at Houston
Rajesh R Yadav, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Patrick M Foye, MD, FAAPMR, FAAEM, Associate Professor of Physical Medicine and Rehabilitation, Co-Director of Musculoskeletal Fellowship, Co-Director of Back Pain Clinic, Director of Coccyx Pain Service (Tailbone Pain Service: www.TailboneDoctor.com), University of Medicine and Dentistry of New Jersey, New Jersey Medical School
Patrick M Foye, MD, FAAPMR, FAAEM is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, Association of Academic Physiatrists, and International Spine Intervention Society
Disclosure: Nothing to disclose.

CME Editor

Kelly L Allen, MD, Regional Medical Director, IMX-Medical Management Services
Disclosure: Nothing to disclose.

Chief Editor

Denise I Campagnolo, MD, MS, Director of Multiple Sclerosis Clinical Research and Staff Physiatrist, Barrow Neurology Clinics, St Joseph's Hospital and Medical Center; Investigator for Barrow Neurology Clinics; Director, NARCOMS Project for Consortium of MS Centers
Denise I Campagnolo, MD, MS is a member of the following medical societies: Alpha Omega Alpha, American Association of Neuromuscular and Electrodiagnostic Medicine, American Paraplegia Society, Association of Academic Physiatrists, and Consortium of Multiple Sclerosis Centers
Disclosure: Teva Neuroscience Honoraria Speaking and teaching; Serono-Pfizer Honoraria Speaking and teaching

 
 
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