Adult-onset Still's disease and its characteristic rash

Still's disease was originally described as one form of rheumatoid arthriti s in children beginning with fever and other systemic symptoms. In rare cas es it may also begin in the adult and is then referred to as adult-onset St ill's disease. The diagnostic criteria include typical rash, arthralgias, b outs of fever, and leukocytosis, as well as lymphadenopathy or splenomegaly , liver dysfunctions, noninfectious angina, and absence of rheumatoid facto r and antinuclear antibodies. We report two adult patients with longstandin g disease whose exanthema guided us to the correct diagnosis. The rash is a finding with high sensitivity. It is characterized by red macules with dis tinct borders and is evanescent. During an acute flare of the rash, gentle friction induces erythematous, isomorphic (Koebner) phenomena,which,as we d escribe here for the first time, may persist longer than the remainder of t he fleeting rash.