Distal extremity swelling with pitting edema in psoriatic arthritis: A case-control study

Objective To evaluate the frequency and the clinical characteristics of dis tal extremity swelling with pitting edema in patients with psoriatic arthri tis (PsA). Methods This was a case-control study of consecutive outpatients with PsA ( old and new diagnosis) observed over a 3-month period in three secondary re ferral centers in Italy As controls we used the two consecutive rheumatic o ut-patients, excluding those with spondylarthropathies, observed after a Ps A patient. The demographic and clinical features were assessed by clinical examination and review of the medical records. Results A total of 183 patients with PsA and 366 controls were evaluated. D istal extremity swelling with pitting edema M ns recorded in 39/183 (21%) P sA patients and in 18/366 (4.9%) controls (p < 0.0001). In 8/39 (20%) patie nts this feature presented as a first, isolated manifestation of PsA, and i n 8 others it was associated with other features of PsA at diagnosis. The u pper and lower extremities were affected, predominantly asymmetrically, in 40% and 60% of the cases respectively. In patients with pitting edema compa red To those without this feature, the frequency of Achilles enthesitis and plantar fasciitis, calculated together was higher (p < 0.05) and the durat ion of arthritis was significantly lower (p = 0.02). In 7 patients the clin ical evidence of a predominant involvement of tenosynovial structures was c onfirmed by MRI. Conclusion Upper or lower distal extremity swelling with pitting edema clue to tenosynovitis, usually unilateral, is a common feature in PsA patients and may represent the first, isolated manifestation of the disease.