[Prevention of allergy by protective skin creams: possibilities and limits]

Despite promising efficacy data for protective creams and many scientifically proven advances that have been achieved concerning the prevention of irritative contact dermatitis, protection against sensitising substances remains a particular problem due to the minimal amounts of allergen that trigger allergic contact dermatitis. Therefore, specific allergen-blocking substances have been tested which are designed to prevent sensitising processes and in particular avoid occurrence of contact dermatitis in already sensitised individuals. In this review, we present the results of current studies mainly focussed on preventing occupational contact dermatitis caused by metal salts, using different chelating agents. In the United States allergic contact dermatitis is often due to strongly sensitising plant allergens of Toxicodendron species, a factor of importance in outdoor professions. Therefore, attempts have been made to use linoleic acid dimers and organoclay materials such as quaternium-18 bentonite for prophylaxis in topical treatments. Most studies investigate effectiveness against experimentally induced allergic contact dermatitis in sensitised volunteers using standardised allergen extracts. Although several preparations showed some benefit by possibly preventing certain quantities of allergen from penetrating the epidermis, further effort will be required before sufficient protective creams with allergen-blocking properties are available for workplaces.