Most common allergies are not associated with the risk for rheumatoid arthritis (RA), but some allergic conditions, including animal dander allergy and atopic dermatitis (AD), are linked with increased RA risk, according to a study published in RMD Open. Vanessa L. Kronzer, MD, and colleagues conducted a case-control study involving 3,515 incident RA cases and 5,429 matched controls to examine the association of allergic conditions with incident RA. A history of any reported allergy was equally common in patients with RA and matched controls (30% and 29%, respectively). There was no association observed for metal, respiratory, food, plant/pollen, or chemical allergies with RA risk. However, there were significant associations seen for animal dander allergy (6% vs 5%; adjusted OR, 1.37), especially in anti-citrullinated peptide antibody (ACPA)-positive RA (adjusted OR, 1.46), and for AD, especially for older adults and/or ACPA-negative RA (adjusted OR, 2.33 at age 80). “The bi-directional association between certain atopic and autoimmune diseases supports a possible association between atopic diseases and RA that merits further study,” the study authors wrote.