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

Abstract

Patients with eczema and other dry skin conditions use moisturizers also when the skin appears healthy. However, moisturizers have been found to change skin barrier function, and it appears that certain combinations of ingredients increase the skin susceptibility to external agents. In the present randomized and single-blind study, the influence of a urea-containing cream on nickel susceptibility in 35 patients with known allergy to nickel was evaluated. Treatment of the volar forearm twice daily for 20 days with the urea cream reduced transepidermal water loss (TEWL). However, the susceptibility to nickel sulfate was not changed by the cream treatment. Clinical scoring of the skin reaction did not show any difference between the untreated and the cream-treated area. Furthermore, the increase in TEWL did not differ between the areas. The absence in correlation between TEWL and skin susceptibility to nickel suggests different penetration pathways through the skin of water and nickel. Measurement of the skin permeability to other substances than water is pertinent to the understanding of the influence of moisturizers on the skin permeability and, ultimately, to their therapeutic efficacy in the prevention of contact eczema due to exposure to harmful exogenous substances.

Artificial reduction in transepidermal water loss improves skin barrier function

“…3,[32][33][34] The lipid-rich cream in the present study has also shown deleterious effects on skin barrier function, with a resulting increase in susceptibility to irritants and allergens, 7,8,13,14 whereas the urea cream has repeatedly been shown to reinforce barrier function. 9,11,16 In this study we were able to confirm previous findings of marginal reductions in skin water loss by application of formulations, 19 but failed to link previously reported differences on skin barrier function with differences in occlusion from the two studied emulsions. Furthermore, we were able to demonstrate an improved skin barrier function by long-term increase in skin hydration induced by a semipermeable silicone membrane.…”

“…13 Increased sensitivity to nickel has also been reported after treatment of nickel-sensitive patients with moisturizers without humectant 14,15 compared with treatment with moisturizers containing humectants. 15,16 In addition, differences in skin reactivity to the vasodilator benzyl nicotinate have been reported between treatments with a lipid-rich cream and a moisturizer containing urea. 17 The role of the proposed 'active' ingredients in the formulations (e.g.…”

Skin Barrier Responses to Moisturizers: Functional and Biochemical Changes

“…It has been suggested that the decreased TEWL and lower response to SLS after treatment with Complex cream was due to its urea content [ 10,11,26 ] . Moreover, it could be expected that the addition of urea to a moisturizer would be benefi cial, as it has been reported that urea replaces water in the skin, leaving the physical properties of the stratum corneum intact [ 44 ] .…”

“…It was previously shown that occlusion of the skin with a semipermeable membrane, mimicking the occlusion effect by a moisturizer, decreased TEWL and susceptibility to an irritant, in a group wearing the membrane 23 h a day for 3 weeks, suggesting changes in skin barrier function [ 49 ] . However, there is no evidence of a correlation between the occlusive properties of creams and their effects on the skin barrier, determined as the degree of irritation after SLS exposure, since Complex cream and a lipid-rich cream show similar occlusive capacity [ 49 ] , but opposite effects on the skin barrier function [ 10,11,15,16,26 ] . Therefore, the detected difference in the effect on the skin barrier is more likely to have causes other than difference in occlusion between the creams.…”

Changes in skin barrier function following long-term treatment with moisturizers, a randomized controlled trial

“…However, there is still a lack of knowledge about the effects of moisturizers on skin barrier function, especially after long‐term treatment. Studies conducted so far, both in healthy and diseased skin, show that some moisturizers may weaken skin barrier function—observed as changes in transepidermal water loss (TEWL) and susceptibility to irritants—while others may strengthen it 1–6 . Moisturizers can also influence skin barrier recovery 1,7 .…”