Hypohidrosis plays a crucial role in the vicious circle of bathing suit ichthyosis: a case with summer exacerbation.

© 2014 The Authors. doi: 10.2340/00015555-1739 Journal Compilation © 2014 Acta Dermato-Venereologica. ISSN 0001-5555 Bathing suit ichthyosis (BSI) is a rare variant of autosomal recessive lamellar ichthyosis (LI). In 2005, Jacyk first reported 13 cases of LI that presented with the characteristic distribution of lesions on the trunk but usually sparing the extremities and the central face (1). Subsequently, Oji et al. (2) showed that BSI is caused by transglutaminase-1 (TG1) deficiency with heatdependent TG1 dysfunction. We and colleagues previously reported a case of BSI with summer exacerbation, suggesting the involvement of a temperature-dependent mechanism (3). However, the mechanism of this temperature-dependent exacerbation remained unclear. In people with acquired idiopathic generalised anhidrosis, the occlusion of proximal coiled ducts results in severe heat intolerance (4). This phenomenon led us to hypothesise that seasonal exacerbation might be associated with hypohidrosis in BSI cases. In this study, we demonstrated that hypohidrosis plays a crucial role in the heating spiral.