Recurrent macrophage activation syndrome (MAS) is very rare. We present the case of an adolescent boy with human leukocyte antigen (HLA) B27-positive ankylosing spondylitis (AS), who experienced episodes of recurrent MAS since he was a toddler. A 16-year-old boy was admitted because of remittent fever with pancytopenia and splenomegaly after surgical intervention for an intractable perianal abscess. He had been...

Reactive arthritis comprises a subgroup within infection-associated arthritides in genetically susceptible hosts. Researchers and clinicians recognize two clinical forms of reactive arthritis which occurs after genitourinary tract infection and after gastrointestinal tract infection. Chlamydia infection has been implicated as the most common agent associated with post-venereal reactive arthritis. Studies have proposed Shigella infection, Salmonella infection, or Yersinia infection as the...