Irritant contact dermatitis (ICD) is a common form of irritation that can occur when human skin is exposed to potential irritants such as surfactants, cutting oils, etc.1, 2 Minimizing exposure to such irritants is recommended but often not practical since exposure is unavoidable in some occupations including farming, firefighting, medicine, etc. To counteract or suppress irritation responses in the skin, anti-irritant agents are employed. These ingredients, whether naturally occurring or man-made, used alone or in formulations, possess the capacity to reduce irritation caused by acute and chronic exposure to irritants.3
To fully prevent or reduce the risk of developing ICD, anti-irritant agents such as barrier creams (BCs) and moisturizers are widely utilized.4–9 Though BCs and moisturizers are not identical, probably due to their ambiguous definitions, the terms BC and moisturizer are often used interchangeably in the literature and the marketplace. The target of BCs is to prevent external noxious substances from penetrating skin, usually in an occupational setting,5, 7–9 whereas moisturizers are frequently used for dry skin conditions as well as to maintain healthy skin.4, 6, 9–11 However, moisturizers and BCs share characteristics, thus it can be difficult to distinguish between the two. Therefore it is suggested that the standard term skin protectant be used when referring to anti-irritants;12 several terms and definitions commonly used in reference to skin protection are summarized in Table 1. Although numerous ingredients have been formulated into finished skin protection products, the US Food and Drug Administration (FDA) has only endorsed 13 ingredients for over-the-counter (OTC) products (see Table 2).
Based on an extensive literature review, this column describes studies and data related to the proposed efficacy of anti-irritant agents for reducing ICD in human skin. To compile this review, a literature search in PubMed, EMBASE and Scopus was conducted, and only research discussing either the prevention or treatment of irritation in human skin was considered. Studies and data conducted on non-human skin were excluded, and emphasis was placed on the studies that included quantitative and qualitative results as well as those that followed evidence-based dermatological guidelines.