Filaggrin loss-of-function mutation R501X and 2282del4 carrier status is associated with fissured skin on the hands: results from a cross-sectional population study

Summary Background Filaggrin metabolites act as osmolytes and are important for skin hydration. Carriers of filaggrin loss‐of‐function mutations have a higher prevalence of atopic dermatitis and dry skin. There is also evidence to suggest that filaggrin mutations increase the risk of hand eczema in atopic individuals. In our clinic, we have observed a distinct phenotype of hand eczema in patients with filaggrin mutation carrier status, characterized by fissured dermatitis on the dorsal aspect of the hands and with only sparse involvement of the palms including fine scaling. Objectives To investigate whether filaggrin loss‐of‐function mutations are associated with skin fissures on the hands and/or fingers in the general population. Methods Participants in a population‐based study were questioned about skin symptoms, genotyped for filaggrin mutation, patch tested for nickel allergy and skin prick tested. Results In an adjusted logistic regression analysis, filaggrin mutation status was significantly associated with fissured skin on the hands and/or fingers in adults (odds ratio 1·93, 95% confidence interval 1·05–3·55) and showed a nearly significant negative interaction with atopic dermatitis (P = 0·055), suggesting that the effect was predominantly in subjects without atopic dermatitis. Conclusions Filaggrin loss‐of‐function mutations seem not only to increase the risk of atopic dermatitis and dry skin but also the risk of fissures on the hands and/or fingers in subjects without atopic dermatitis. Prophylactic emollient therapy should be particularly encouraged in filaggrin loss‐of‐function mutation carriers. See also the Commentary by Uter