ABSTRACT
Diagnostic in vivo skin tests are used in dermatology to detect and define the
possible exogenous chemical agent that causes a skin disorder, and hence are
critical in their scientific documentation. Such chemical agents often cause skin
disorders by hypersensitivity mechanisms, which can thus be diagnosed by a
provocative test (Lauerma and Maibach, 1995). The anatomical advantage of
studying skin disorders is that the skin is the foremost frontier of the human
body and therefore easily accessible for testing. Although it has been shown
that differences in the reactivity of different skin sites exist, many causative
agents may be tested locally on one skin site, thus exposing only limited areas
of skin to the diagnostic procedures. Such procedures include patch, intradermal,
prick, scratch, scratch-chamber, open, photo, photopatch, and provocative use
tests. In cases of some generalized skin reactions, however, systemic exposure
to the external agent may be necessary for diagnosis.
