A Novel Multifactorial Approach to Developing Mild Laundry Detergents and Assessing Their Relative Mildness

December 2017 | Volume 16 | Issue 12 | Original Article | 1235 | Copyright © December 2017


Joseph F. Fowler Jr. MD,a Matthew J. Zirwas MD,b Lisa Napolitano BS,c Meghan Russell BS,c and Janet Coope-Epstein PhDc

aUniversity of Louisville and Division of Occupational Medicine at the University of Kentucky, Louisville, KY bMount Carmel East and West Hospitals, Columbus, OH; Private Practice, Columbus, OH cThe Sun Products Corporation, a Henkel Company; Stamford, CT

Abstract

INTRODUCTION: Dermatologists are becoming more aware of the irritant and allergic potential of laundry detergents that incorporate harsh surfactants and potentially sensitizing ingredients. It is difficult however for the physician to distinguish one laundry detergent from another because the only distinguishing feature advertised tends to be the lack of dyes and fragrances.

DESIGN: A new objective method was developed for measuring the harshness of laundry detergents using a three-pronged laboratory testing approach consisting of zein, corneosurfametry, and cytokine testing. Combing these methods, a Detergent Mildness Index was created which conveniently provides a single value by which products can be compared.

Results: A new mild laundry detergent was formulated with ingredients carefully selected by dermatologists who are experts in con-tact dermatitis. The irritancy potential of the formula was measured using the Detergent mildness index score. Compared to 11 other commercial laundry detergents marketed for sensitive skin, the new formula is measurably the mildest formula.

Discussion: The Detergent Mildness Index provides dermatologists with an objective method to compare commercial laundry deter-gents. Currently the only method available is patch testing, this new test is able to more finely differentiate between products and thus enables more informed recommendations on laundry detergent choices for their patients with sensitive skin.

J Drugs Dermatol. 2017;16(12):1235-1239.

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INTRODUCTION

Dermatologists often recommend laundry detergents that are free of harsh chemicals, fragrances and dyes.1 New methodologies have enabled the development of a laundry detergent with a new level of mildness.

Chemistry of Surfactants

All detergents contain surface-active agents (surfactants) which possess cleaning properties and help lift dirt from fabric.2 Surfactants may unintentionally and negatively interact with skin when in contact with it for long periods of time.3,4 Through direct contact with clothing containing detergent residue, there is the potential for irritant and allergic contact dermatitis, which is likely to be exacerbated in patients with existing dermatological disorders. One publication suggests that the amount of laundry residue deposited on fabric is 2.5%.5

Effects of Surfactants on Skin

Upon prolonged contact with the skin, surfactants can adsorb to keratin, and cause subsequent denaturation, transient swelling and hyperhydration.6,7 Swelling increases the risk of surfactant penetration into deeper layers of the skin, and may lead to long-term skin dryness. Lipids are also susceptible to solubilization by surfactants, leading to increased permeability and destabilization of lipid bilayers.2,6 Persistent and unresolved stratum corneum-surfactant exposure can lead to long-term deleterious damage in some patients.8 At first, the skin mounts a local immune response. Over time, a systemic response may occur. The inflammatory cascade is stimulated when keratinocytes in the epidermal layer secrete key cytokines, such as interleukin 1α (IL-1α) and tumor necrosis factor α (TNFα).4,9 Initial symptoms include pruritus, erythema, and xerosis with a glazed, parched appearance.2,10,11 Over time, frequent contact with surfactants can change skin permeability and texture.3 Symptoms then progress to eczematous dermatitis, resulting in skin thickening, hyper- or hypopigmentation, and scaling, fissuring, and lichenification.8

Patch Testing

New mild detergent formulations are expected to be thoroughly evaluated for safety and mildness.12 Patch testing on normal healthy volunteers is commonly used in the industry to demonstrate the expected safety profile during normal consumer usage. New methodologies have the potential to provide dermatologists with additional information and enable more