Diamond HS, Al Hammadi A: Fast five quiz: can you identify psoriatic arthritis and initiate the best treatment practices?
Medscape. Available at: http://reference.medscape.com/viewarticle/835807. Accessed September 20, 2019.)| false
Winchester R, Minevich G, Steshenko V, et al: HLA associations reveal a genetic heterogeneity in psoriatic arthritis and in the psoriasis phenotype. Arthritis Rheum64: 1134, 2012.10.1002/art.3341522006066)| false
Venables PJW, Maini RN: Diagnosis and Differential Diagnosis of Rheumatoid Arthritis, edited byJRO-Dell, PLRomain, Waltham, MA, UpToDate. Available at: https://www.uptodate.com. Accessed September 20, 2019.
Venables PJW, Maini RN:
Diagnosis and Differential Diagnosis of Rheumatoid Arthritis, edited byJRO-Dell, PLRomain, Waltham, MA, UpToDate. Available at: https://www.uptodate.com. Accessed September 20, 2019.)| false
Chandran V, Cook RJ, Edwin J, et al: Soluble biomarkers differentiate patients with psoriatic arthritis from those with psoriasis without arthritis. Rheumatology (Oxford)49: 1399, 2010.10.1093/rheumatology/keq105)| false
Gladman DD, Farewell VT, Wong K, et al: Mortality studies in psoriatic arthritis: results from a single outpatient center. II. Prognostic indicators for death. Arthritis Rheum41: 1103, 1998.962702110.1002/1529-0131(199806)41:6<1103::AID-ART18>3.0.CO;2-N)| false
Shmerling RH, Delbanco TL: How useful is the rheumatoid factor? An analysis of sensitivity, specificity, and predictive value. Arch Intern Med152: 2417, 1992.10.1001/archinte.1992.004002400410061456851)| false
Psoriatic arthritis is an uncommon, chronic inflammatory disease. Laboratory testing for psoriatic arthritis, although necessary for a complete work-up, is generally nondiagnostic for most patients. We present a case of a 26-year-old woman with unilateral plantar forefoot pain and swelling that was diagnosed as psoriatic arthritis. The diagnosis was made without the benefit of skin manifestations or definitive laboratory results, other than those from laboratory tests performed for an initial evaluation of acute-phase reactants. Radiographs showed nonspecific subchondral bone changes at a few metatarsophalangeal joints of the involved foot that suggested an inflammatory arthropathy. This case illustrates that the absence of specific serum markers for psoriatic arthritis can make its diagnosis challenging, especially in the absence of dermatologic changes of psoriasis.
Corresponding author: James Mahoney, DPM, Des Moines University, College of Podiatric Medicine & Surgery, 3200 Grand Ave, Des Moines, IA 50312-4198. (E-mail: email@example.com)