Research Summary
Irritant contact dermatitis (or irritant contact eczema) is an inflammatory state of the skin caused by exposure to chemical and/or physical influences. It is a prevalent disease, and irritant contact dermatitis (ICD) can be divided into two types:
1. Acute ICD, which develops after a single contact with a strongly irritant substance.
2. Subacute/chronic ICD, which develops as a result of cumulative, subliminal damage to the skin due to contact with weak irritants.
This thesis focuses on chronic ICD caused by exposure to detergents. To simulate the use of detergents in daily life, it is important to adjust the laboratory exposure conditions to closely match those in everyday practice. This makes longitudinal exposure studies necessary. The investigations presented in this thesis involved repeated short-time applications of low-molarity detergent solutions over a prolonged period of time. To evaluate the effects of these applications on human skin, transepidermal water loss (TEWL) measurements and visual assessments were used.
The objectives of the studies described in this thesis were as follows:
1. To compare the sensitivity of TEWL measurements and visual evaluations in detecting early skin changes caused by detergents.
2. To classify detergents according to their skin irritant potency.
3. To assess differences between individuals in susceptibility to detergents.
4. To investigate the extent to which personal characteristics (such as pre-exposure barrier function, history of atopic dermatitis, and skin dryness) determine susceptibility to detergents.
This thesis is divided into two sections:
In **Section I** (Chapters 1-4), a literature review covers the following subjects:
- Etiology and prevalence of chronic irritant contact dermatitis (Chapter 1).
- Structure and function of the skin barrier (Chapter 2).
- Influence of detergents on the skin (Chapter 3).
- Characteristics of vulnerable skin (Chapter 4).
In **Section II** (Chapters 5-10), a series of in vivo investigations on the influence of repeated exposure of the skin to low-molarity solutions of various detergents is presented. All studies were conducted with volunteers who provided informed consent, and approval was obtained from the medical-ethical committee of the State University Hospital Groningen.