Decreased oxidative state in non-lesional skin of atopic dermatitis

The stratum corneum (SC), as the skin layer most exposed to various environmental factors, is particularly susceptible to oxidative stress. Due to the high lipid content of the SC, lipophilic antioxidants such as alpha-tocopherol are expected to play a major role in scavenging reactive oxidant intermediates produced during oxidative stress.

Since the skin of atopic dermatitis patients has an impaired barrier function, we wondered if they were more susceptible to environmental oxidative stress than healthy subjects.

SC was collected by scraping the forearm of 14 healthy volunteers and 14 patients with atopic dermatitis; then, alpha-tocopherol and lipid peroxide concentrations were assessed by high-performance liquid chromatography and ferrous oxidation, respectively.

The SC from atopic patients showed a higher concentration of alpha-tocopherol (16.1 +/- 2.2 nmol/g) as compared to healthy controls (7.7 +/- 0.9 nmol/g; p < 0.01), as well as a slightly but significantly lower concentration of lipid peroxides (1,353 +/- 128 and 1,818 +/- 154 nmol/g for atopic dermatitis patients and healthy controls, respectively; p < 0.05).

These results show that the SC of atopic dermatitis patients exhibits a significantly less pronounced oxidative state. This may be the consequence of an increase in cutaneous antioxidant defences due to chronic inflammation.