Eighteen patients with adult-onset Still’s disease have been followed up for 3–22 years in our department. Initial manifestations were fever with skin rash in 14 patients, fever, skin rash and sore throat in two, skin rash in one and arthralgia in one. During the follow-up period, typical skin rash was seen in all patients, of them five patients (29%) revealed atypical skin rash simultaneously. Atypical rash included persistent erythema with pigmentation in two, persistent plaques and papules with linear erythema in two and edema of the eyelids mimicking dermatomyositis in one. Persistent papules and plaques revealed histologically characteristic features, such as dyskeratotic keratinocyte and liquefaction degeneration as well as a sparse superficial dermal infiltrate containing scattered neutrophils. In patients of chronic articular type and polycyclic systemic type, atypical skin rash, lymphadenopathy and hyperferritinemia were noted to be significantly higher than those of monocyclic type. These factors might be prognostic factors of adult-onset Still’s disease in our study.