Effect of a moisturizer on skin susceptibility to NiCl2

The aim of this study was to evaluate whether a moisturizer used on normal skin can increase skin response to allergens. Twelve nickel-allergic volunteers applied a lipid-rich moisturizer on the upper arm 3 times daily for 7 days, while the other upper arm served as a control. A control group followed the same treatment protocol. Following treatment with moisturizer, patch tests with 1% NiCl2 aqueous solution were applied on each upper arm. After 24 and 72 h, skin reactions were evaluated blinded by clinical scoring, and by bioengineering methods measuring transepidermal water loss, skin colour and skin thickness. In the nickel-allergic group the strength of patch-test reactions was increased on the moisturizer-treated arm as evaluated by clinical scoring after 24 h and by measurement of transepidermal water loss and skin thickness after 72 h. In the control group, no significant differences were found. Our findings show that threshold values for elicitation of allergic reactions in already sensitized individuals may be influenced by use of lipid-rich moisturizers.