HLA-B27 spondyloarthritis and spotted fever rickettsiosis: case-based review.

Rickettsia rickettsii, a tick borne disease, is the pathogen responsible for inducing Rocky Mountain Spotted Fever (RMSF), an illness that can progress to fulminant multiorgan failure and death. We present a case where R. rickettsii, acquired on a camping trip, precipitated a flare of peripheral arthritis and episcleritis in an HLA-B27 positive patient. Although Yersinia, Salmonella, Mycobacteria, Chlamydia, Shigella, Campylobacter, and Brucella have been previously associated with HLA-B27 spondyloarthritis, this unusual case demonstrates that obligate intracellular rickettsial organisms, and specifically, R. rickettsii, can also induce flares of HLA-B27 spondyloarthritis. Rickettsial infections in general can rapidly become fatal in both healthy and immunosuppressed patients, and thus, prompt diagnosis and therapy are required.