ABNORMAL SKIN IRRITANCY IN ATOPIC-DERMATITIS AND IN ATOPY WITHOUT DERMATITIS

Background and Design: Past observations have shown increased irritanc y in patients with ''conditioned hyperirritability'' due to active der matitis, including atopic dermatitis (AD). In less active atopic condi tions, irritancy levels are less certain. We have utilized 48-hour Fin n Chamber testing with graded dilutions of sodium lauryl sulfate to de tect irritancy thresholds in well-defined groups of patients with AD, inactive AD, and allergic respiratory disease with no dermatitis and i n normal nonatopic subjects. Results: Significantly greater frequency of response to sodium lauryl sulfate in both AD groups and also in pat ients with allergic rhinitis with no dermatitis was seen. Effective co ncentrations of sodium lauryl sulfate causing irritation in 50% or mor e of subjects (ED(50)) ranged from 0.0625% to 0.31% in all atopic grou ps, percentages that were significantly lower than the normal ED(50) o f 0.60%. Response intensity was also significantly greater in each ato pic group. Conclusions: Our results showed significantly greater irrit ant responses in atopic subjects with no skin disease or in subjects w ith inactive AD and confirmed past findings that showed greatly increa sed irritancy in patients with active AD. We hypothesize that abnormal intrinsic hyperreactivity in inflammatory cells, rather than in skin cells, in atopic individuals predisposes to a lowered threshold of irr itant responsiveness.