Epidemiology

FS is a rare extra-articular manifestation of rheumatoid arthritis (RA) and is estimated to occur in <1% of RA patients.[5]

True FS prevalence is difficult to ascertain because many affected patients remain asymptomatic. In addition, with the advent of early and intensive suppression of RA disease activity with disease-modifying antirheumatic drugs (DMARDs) and biologic treatments, FS may now be occurring even less frequently and may be less severe.[6]

FS tends to occur in the fifth to seventh decades of life, with a female-to-male ratio of 1.6:1.[2] It is uncommon in children and in people of black ancestry.[7] The HLA-DR4 antigen is strongly associated with FS, so these patients tend to have a strong family history of RA.[3] In patients with FS, RA is typically present, on average, 10 to 20 years before neutropenia develops.[2]

Use of this content is subject to our disclaimer