Spondyloarthritis with onset after age 45.

The ASAS (Assessment in SpondyloArtrhritis international Society) classification criteria for axial and peripheral spondyloarthritis permit to classify patients with age at disease onset less than 45 years. Nevertheless, these two forms of spondyloarthritis may begin after the age of 45. With the longer duration of the life expectancy, patients with this late-onset form of spondyloarthritis may be more frequently recognized in the near future. A small percentage (ranging from 3.5 to 6 %) of patients with axial SpA, as defined by the modified New York criteria, have onset of their disease after 45 years of age. Relatively more frequent is the late onset form of peripheral spondyloarthritis with the characteristics of undifferentiated spondyloarthritis. Its clinical spectrum is as broad as it is in children and very young adults. Psoriatic arthritis frequently begins over the age of 45 and occasionally after the age of 60. Some old studies had suggested than elderly-onset psoriatic arthritis is more severe than younger-onset disease, but a recent study found no such difference, and further studies are needed.