Effects of Pretreatment with a Urea-containing Emollient on Nickel Allergic Skin Reactions

Abstract

The aim of this study was to evaluate the effect of a moisturizer containing urea on allergic contact dermatitis. Twenty-five nickel-sensitized patients and five controls (non-sensitized volunteers) applied such a moisturizer on the volar side of one forearm twice daily for 20 days, while the other forearm served as the control. After treatment with the moisturizer, patch tests with 0%, 0.5% and 2% NiSO4 in petrolatum were applied in a randomized manner on each arm. After 72 h, the skin reactions were blindly evaluated by clinical scoring and by measuring transepidermal water loss and electrical impedance. After treatment, the baseline transepidermal water loss values were lower and the baseline magnitude impedance index values were higher on the pretreated forearm. According to clinical scoring and measurements with the two physical measurement techniques, the degree of the patch test reactions was equal. All control subjects had negative nickel tests. We concluded that the skin reactivity to nickel in nickel-sensitized patients is not significantly affected by use of the urea-containing moisturizer.

Nickel Susceptibility and Skin Barrier Function to Water after Treatment with a Urea-Containing Moisturizer

“…TEWL is also suggested to serve as an indicator of the permeability of the skin to topically applied substances [52,53] . In the present study, treatment of normal skin with a urea-containing cream reduced TEWL, in accordance with previous fi ndings [33,35] . If TEWL refl ects barrier capacity, then the decreased TEWL value suggests an improved barrier function to penetration of nickel.…”

“…This scale is considered to be more sensitive for detection of possible differences in the strength of the skin reaction than the commonly used scale for detection of allergy, which was used in the previously reported study on some of the included subjects [33] .…”

“…Twenty-fi ve of the subjects were also analyzed using impedance measurements and reported elsewhere [33] . Inclusion criteria were a clinically proven history of nickel allergy, while subjects with current active eczema were excluded.…”

“…Studies of human skin in vivo show that longer treatment times (10-20 days) with 5-10% urea decrease TEWL, whereas treatment for a limited number of days (1-2 days) appears to increase TEWL [33][34][35] . TEWL measurements have also been combined with challenge of the skin with SLS to elucidate possible changes in susceptibility to irritation ( table 1 ) [35,36] .…”

The Use of Urea in the Treatment of Dry Skin

“…In vitro measurements on piglet stratum corneum suggest that urea markedly decreases TEWL [ 77 ] . Studies on humans indicate that treatment for a limited number of days (1 to 2 days) with 5-10% urea may increase TEWL, whereas longer treatment periods (10-20 days) decrease TEWL, Table 33.4 [ 37,[79][80][81] .…”