Dermatology Online Journal

Psoriasis and psoriatic arthritis, axial type
Katherine L. White
Dermatology Online Journal 7(2): 12

New York University Department of Dermatology

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History

This 45 year-old man presented with a 20 year history of psoriasisi involving his scalp, elbows, lower back, buttocks, and knees. The patient has a 20-year history of psoriasis, progressive psoriatic arthritis refractory to numerous treatments. His arthritis and skin lesions were unresponsive to methotrexate 30 mg weekly. A trial of azathioprine was ineffective. He developed leukopenia on sulfasalazine. He has been treated in the past with broad-band UVB phototherapy, PUVA photochemotherapy, and acitretin. For the past year, he has received narrow-band UVB phototherapy. On April 28, 2000, he was started on etanercept therapy. He reported decreased morning stiffness, increased joint mobility, and improvement of skin lesions (30% BSA to approximately 5% BSA). Other than mild and transient injection site erythema and pruritus during the first month of etanercept treatment, he experienced no adverse effects. Past medical history includes hypertension, hypercholesterolemia, and numerous non-melanoma skin cancers. A brother has psoriasis and psoriatic arthritis. Current medications are simvastatin, hydrochlorothiazide, and lisinopril.

Physical Examination

Small, erythematous plaques with scale were present on the scalp, elbows, lower back, buttocks, and knees. There was limited ability to open the jaw, no mobility of the cervical spine, fusion of the right wrist, surgical fusion of the second and third digits of the right hand, and sausage-shaped deformity of the proximal interphalangeal joints.

Figure 1

Laboratory Data

Prior to initiation of etanercept therapy, a complete blood count, chemistry profile, liver function tests, and urinalysis were normal. An erythrocyte sedimentation rate was 38 mm/hr and C-reactive protein 1.22 mg/dl. After treatment, the complete blood count, chemistry profile, liver function tests, and urinalysis remained normal. An erythrocyte sedimentation rate was 13 mm/hr and C-reactive protein 0.55 mg/dl. Radiographs showed diffuse fusion of the apophyseal joints and intervertebral discs at all levels of the cervical spine, fused sacroiliac joints, and moderate-to-severe inflammatory arthritis of the hands and feet.

Comment

Psoriatic arthritis is an inflammatory arthritis that affects 5 to 7% of patients with psoriasis. It is classified as a seronegative spondyloarthropathy. Recent advances in the understanding of the immunopathogenesis of rheumatoid arthritis have led to the development of a new class of therapeutic agents that block the action of the pro-inflammatory cytokine tumor necrosis factor (TNF). Etanercept (Enbrel) is a recombinant dimer composed of two soluble TNF receptor molecules fused to the Fc fragment of human IgG1. It is approved for treatment of moderate-severe rheumatoid arthritis refractory to other treatments and for polyarticular juvenile rheumatoid arthritis, either as monotherapy or in conjunction with methotrexate. It is supplied as a powder requiring reconstitution with sterile water prior to subcutaneous injection. The dose is 25 mg subcutaneously two times per week. Etanercept is contraindicated in patients with sepsis. Randomized, controlled trials have shown that the efficacy of etanercept swiftly and significantly reduces the signs and symptoms of rheumatoid arthritis. Safety has been demonstrated for up to 43 months of therapy in rheumatoid arthritis. Approximately 40% of patients experience mild injection site reactions including erythema, pruritus, and induration. These reactions tend to be more common at the beginning of treatment.

Analysis of the cytokine levels in the synovial fluid of patients with psoriatic arthritis showed patterns of elevated pro-inflammatory cytokines, such as TNF, IL-1, IL-6, and IL-8, similar to those seen in rheumatoid arthritis. In addition, TNF levels were elevated in psoriatic skin lesions. These observations have led to investigation of the efficacy of TNF inhibitor therapy for psoriatic arthritis and psoriasis. Preliminary data suggest that etanercept may be efficacious in treatment of psoriatic arthritis and psoriasis.

References

Ettehadi P, et al. Elevated tumour necrosis factor-alpha biological activity in psoriatic skin lesions. Clin Exp Immunol 96:146, 1994

Partsch G, et al. Highly increased levels of tumor necrosis factor-alpha and other inflammatory cytokines in psoriatic arthritis synovial fluid. J Rheumatol 24:518, 1997

Mooreland LW, et al. Etanercept therapy in rheumatoid arthritis. Ann Intern Med 130:478, 1999

Weinblatt ME, et al. A trial of etanercept, a recombinant tumor necrosis factor receptor: Fc fusion protein, in patients with rheumatoid arthritis receiving methotrexate. N Engl J Med 340:253, 1999

Lovell DJ, et al. Etanercept in children with polyarticular juvenile rheumatoid arthritis. N Engl J Med 342:763, 2000

Mease PJ, et al. Etanercept in the treatment of psoriatic arthritis and psoriasis: a randomized trial. Lancet 356:385, 2000

Mooreland LW, et al. Long-term use of Enbrel (etanercept) in patients with rheumatoid arthritis: North American experience. Data on file: Immunex Corporation, Seattle, WA

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