Sensitive skin and skin irritation. Characteristics and diagnostic tools.

Although the prevalence of sensitive skin proves to be extensive across
industrialized countries, the phenomenon is imprecisely defined and morphologic
or physiological identification has failed. Sensitive skin is mainly
characterized by exaggerated perceptions burning, stinging and itching
sensations and pain. Translation of the subjective perceptions to more
objective biophysical measurements might be the key in the identification and
understanding of sensitive skin. According to our knowledge, it is not clear
whether the consumers perception of excessive discomfort following light-based
or mechanical challenges is related to a *more general* sensitive skin.

Objective: The primary objective is to investigate whether sensitive skin
fundamentally differs from *normal skin*. In this study, we try to identify the
morphological and functional characteristics of sensitive skin by provocation
of the skin with different challenges and evaluation by noninvasive biophysical
measurements, and immunohistochemical analysis of biopsies. By evaluation of
sensitive skin from different perspectives, we try to identify a diagnostic
tool to detect sensitive skin. Furthermore, by mechanical provocation and
provocation with light, the skin reactions are compared to assess whether these
reactions have similarities and may refer to a sensitive skin as a container
term with similar skin reactions triggered by different challenges.

Study design: The pilot study is an explorative observational study. Subjects
with sensitive skin are compared with subjects without sensitive skin.

Participation in the study does lead to direct benefit for the subjects. Before
the volunteers will give informed consent, we will inform them that attending
in this research is not in any way beneficial for them. When the volunteer,
despite of this, does wish to attend in this study, most likely he or she will
do this to make a contribution to science. Considering this, we are of the
opinion that a study with short follow-up time and only minimal invasive
techniques, is legitimate. Subjects are selected by questionnaire. In total,
the volunteers visit the research site three times. The first visit includes
stimulation in the morning and evaluation after 30 minutes and after 8 hours
and therefore, this first visit is time consuming. Subjects are stimulated with
one of the three selected methods, which all may result in physical discomfort,
experienced as prickling or burning feeling or itch. Slight erythema is
expected to occur. The skin responses are assessed by non-invasive methods that
do not significantly interact with the skin. Punch biopsies may cause some
physical discomfort. Local anaesthesia is performed before punch biopsies are
performed and this procedure may be experienced as painful. The risk of visible
scar formation is low, since the lesion is small.