Stratum Corneum Ceramide Profiles Provide Reliable Indicators of Remission and Potential Flares in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease. Prevention of exacerbation of AD is a crucial issue for all physicians. However, exacerbation of AD often is seen during reduction of AD treatment, even with appropriate follow-up by tapered topical corticosteroids and daily topical moisturizers, indicating the need for good indicators of AD remission. We hypothesized that the presence of mutations in FLG or the stratum corneum ceramide profile on AD remission phase may predict the ease of AD exacerbation. This study examined the differences in the frequency of FLG mutations or stratum corneum ceramide profiles (stratum corneum levels and carbon chain length for 11 ceramide classes [ceramides containing nonhydroxy fatty acids and dihydrosphingosines; nonhydroxy fatty acids and sphingosines; nonhydroxy fatty acids and 6-hydroxysphingosines; nonhydroxy fatty acids and phytosphingosines; a-hydroxy fatty acids and dihydrosphingosines; a-hydroxy fatty acids and sphingosines; a-hydroxy fatty acids and 6-hydroxysphingosines; a-hydroxy fatty acids and phytosphingosines; ester-linked fatty acids, o-hydroxy fatty acids, and sphingosines; ester-linked fatty acids, o-hydroxy fatty acids, and 6-hydroxysphingosines; and ester-linked fatty acids, o-hydroxy fatty acids, and phytosphingosines]) at AD remission phase between the two AD study groups: subsequent exacerbation (‒) and (+) of AD. The frequency of FLG mutations did not differ between the study groups. On the other hand, the carbon chain lengths of ceramides containing nonhydroxy fatty acids and dihydrosphingosines, nonhydroxy fatty acids and sphingosines, and nonhydroxy fatty acids and 6-hydroxysphingosines were shorter in the exacerbated AD group than in the maintained-AD group. Thus, the stratum corneum ceramide profile at the remission phase of AD is a potential biomarker, predicting the likelihood of substantial AD remission or subsequent AD exacerbation.