Cutaneous manifestations of adult‐onset Still's disease: A comparative study between young‐onset and elderly‐onset groups

We investigated the detailed characteristics and proportions of typical and atypical rashes in 28 patients with adult-onset Still's disease (AOSD) by retrospectively examining the clinical symptoms and pathological features. The patients consisted of six males and 22 females aged between 23 and 85 years. The skin rashes observed in the study population were as follows: (i) typical rash in six cases, (ii) atypical rash in 19, and (iii) both typical and atypical rash in three cases (in all three cases, typical rash preceded atypical rash). Furthermore, we classified atypical rashes into persistent pruritic papules and plaques (PPPP) and others. In 22 cases of atypical rashes, 10 cases had PPPP. In a comparison between young-onset (<65 years) (n = 16) and elderly-onset (≥65 years) (n = 12) AOSD cases, typical rashes were observed more frequently in the young-onset cases. Regarding atypical rashes, PPPP was significantly more common in the elderly-onset cases.