• bath oil;
  • detergents;
  • irritant contact dermatitis;
  • shower oil;
  • skin blood flow;
  • surfactants;
  • transepidermal water loss


Background  Difficulties in avoiding weak irritants may contribute to chronic contact dermatitis. A large variety of shower and bath oils are claimed to be suitable for use on dry skin because of their mildness and because they deposit a protective oil film on the skin.

Objectives  The aim of the present study was to investigate possible differences in the irritation potential of eight shower or bath oils and to investigate whether surfactant residues may form a reservoir of irritant substance on the skin.

Patients and methods  The study was double-blind and randomized using healthy human volunteers. The inherent capacity of the products to induce irritation was determined using conventional patch test techniques. Detection of potentially irritant residues was done by occlusion of the treated and rinsed skin area, followed by evaluation of the biological response. Instrumental measurements of transepidermal water loss and superficial skin blood flow served as indicators of the injurious effects of the products.

Results and conclusions  The results showed large differences between the products in irritant potential. Some did not irritate skin more than water, whereas others demonstrated considerably damaging effects. Moreover, the study proved the presence of barrier-impairing residues on the skin after rinsing with water. Thus, instead of protecting the skin, some formulations may induce subclinical injuries and delay skin barrier function recovery with prolonged risk for patients with eczema.