ORIGINAL ARTICLE Treatment of cloth with a fabric softener ameliorates skin dryness Kenichi ISODA, 1 Yutaka TAKAGI, 2 Takashi KITAHARA, 2 Yutaka SANO, 2 Ikuo SUGANO, 2 Kumi UMEDA-TOGAMI, 3,5 Koji UMEDA, 1,3 Keiichi YAMANAKA, 1 Tomomi YAMADA, 4 Hitoshi MIZUTANI 1 1 Department of Dermatology, 5 Institute of Human Research Promotion and Drug Development, Mie University Graduate School of Medicine, 2 Kao Corporation, Tokyo, 3 KSK Laboratories Inc., Tsu, and 4 Clinical Trials Research Center, Mie University Hospital, Tsu, Japan ABSTRACT Dry skin is a condition characterized by impaired skin barrier function including atopic dermatitis and senile ecze- mas. Fabric softening chemicals (FSC) smoothens the surface of fabrics and thus decreases friction with the skin. Scientific evaluation of fabric softener on skin dryness is very limited. We evaluated the effectiveness and safety of FSC-treated T-shirts in subjects with dry skin. This is a randomized double-blind control study that included 40 male volunteers with apparent dry skin. Subjects were randomly divided into two groups: 20 men received 28 pieces of FSC-treated T-shirts wearing them for 4 weeks, and another 20 men received non-treated T-shirts. The effect of trial was evaluated by visual grading, subjective symptom, stratum corneum water content (SCWC), transepidermal water loss (TEWL), and dermoscopic skin surface analysis on days 0, 7, 14 and 28. A significant improvement of SCWC was observed in the skin of the shoulder (days 7–28) and lateral abdomen (day 14) wearing the treated T-shirts, but not in the non-treated T-shirts. In a stratified analysis of the low and high SCWC group, significant improvement was identified in the low SCWC groups but not in high SCWC groups. The visual grading of the shoul- der improved significantly in the treated T-shirts group. No significant improvement was found in TEWL, dermo- scopic analysis and subjective symptom in both groups. No remarkable side-effect was identified throughout this investigation. Addition of a fabric softener during clothes laundering is a potent preventive tool for dry skin. Key words: atopic dermatitis, dry skin, fabric softening chemical, laundering, skin barrier, xerosis. INTRODUCTION The skin, the frontline defense of the body, is exposed to numerous exogenous stimuli including physical stress (rubbing, scratching, trauma, ultraviolet), thermal stress, and chemical stress (detergents, cosmetics, preservatives). Epidermal keratinocytes proliferate from basal layers to the stratum spinosum and finally forms the stratum corneum after terminal differentiation. This stratum corneum is formed by smooth multiple layers containing hard corneal cells and intercellular lipids. This watertight configuration defends the skin from exogenous stimuli and water absorption. The skin barrier also protects transepider- mal loss of body fluids and maintain homeostasis of skin and internal organs. Damage of the stratum corneum by physical, chemical and immunological stress (scratching, degreasing by detergents and der- matitis) disrupts the skin barrier function. 1 This com- monly causes exacerbations of atopic dermatitis and xerosis in the elderly. Skin stress by friction with fab- rics is believed to cause minor trauma to the skin, and causes itching and impairment of the skin barrier. 2 Subsequently, it occasionally results in xerosis and Correspondence: Hitoshi Mizutani, M.D., Ph.D., Department of Dermatology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan. Email: h-mizuta@clin.medic.mie-u.ac.jp Received 6 October 2009; accepted 22 July 2010. doi: 10.1111/j.1346-8138.2010.01084.x Journal of Dermatology 2011; 38: 685–692 Ó 2010 Japanese Dermatological Association 685