Admission rates of atopic dermatitis and psoriasis vulgaris from 1912 to 1994.

Abstract

Western Europe appears to experience an increasing prevalence of atopic dermatitis (AD). The duration of this epidemie and its effects on hospital admission are unknown. Knowledge of the changing admission patterns may have implications for the future causal investigations. Records were examined to determine the long-term changes in hospital admission due to atopic dermatitis and psoriasis vulgaris. The prevalence among hospitalised patients was assessed by the number of patients treated in a given year. To compensate for other factors affecting hospital admission an index of AD prevalence relative to psoriasis in admitted patients was calculated. Two periods were compared: 1912-1937 and 1983-1994. A significantly increasing number of patients with either diagnosis were treated (P<0.0001), reflecting the increased general efficiency of the health system and of derma­tological treatment. Psoriasis-admissions appeared to increase according to a simple equa­tion of a higher order, while AD-admissions increased exponentially. The index increased in a linear way (P<0.0001) and if out-liers were excluded the current index of relative AD prevalence could be predicted from the 1912-1937 trend. The data suggest that rising prevalence rates in society are reflected by rising numbers of hospital admissions through the major part of this century. The rise in AD admissions has exceeded the rise in psoriasis admissions, and the need for further therapeutic develop­ments in AD is therefore stressed. It is speculated that the increasing in-hospital predomi­nance of AD over psoriasis may reflect long-term changes in the prevalence of AD.