We aimed to assess the influence of co-existing atopy on the prognosis of enthesitis-related arthritis (ERA). Patients diagnosed with ERA between March 2006 and August 2012 were enrolled in a prospective cohort study and followed for 2 years. Management of patients was evaluated using the American College of Rheumatology (ACR) pediatric (Pedi) 30/50/70 criteria and laboratory variables. A total of 151 ERA patients were enrolled at diagnosis and were divided into those with atopy (n = 62) and those without (n = 89). When compared with the non-atopic group, atopic patients had significantly more active joints at disease onset (4.72 vs. 3.75), more joints with limitation of motion (LOM) (1.45 vs. 0.87), more painful joints (3.61 vs. 2.80), and more swollen joints (1.02 vs. 0.69) (p < 0.05 for all comparisons). At 3, 6, 12, 18, and 24 months, fewer ERA patients with atopy reached the ACR Pedi 50 and 70 criteria (at 3 months, 25.8 vs. 60.7 % and 11.3 vs. 34.8 %, respectively; at 6 months, 50 vs. 77.5 % and 22.6 vs. 58.4 %, respectively; at 12 months, 53.2 vs. 70.8 % and 33.9 vs. 55.1 %, respectively; at 18 months, 62.9 vs. 86.5 % and 56.5 vs. 78.7 %, respectively; at 24 months, 66.1 vs. 89.9 % and 61.3 vs. 78.7 %, respectively; all p < 0.05). During the 2 years of follow-up, the number of flares was significantly higher in ERA patients with co-existing atopy (1.48 vs. 0.70, p < 0.05).
Co-existing atopy in children with ERA may exert an adverse influence on ERA, with atopic patients manifesting more active disease at diagnosis and poorer outcome. \