ABSTRACT
Human skin is exposed to a number of chemicals and drugs throughout our entire lives. Following percutaneous absorption, a chemical and or its metabolites may cause toxicity locally or in another organ, distant from the point of entry. Although not generally appreciated, some chemicals are more toxic, at least in animals, when applied topically rather than orally. Furthermore, many compounds are absorbed to a greater degree from the skin than gastrointestinal (GI) tract, and whole body exposure can produce systemic absorption up to grams of material. This chapter focuses on the limited epidemiologic material available and depends mostly on case reports. Many compounds dermally absorbed are capable of producing systemic side effects whose occurrence and severity depends largely on the many factors that can affect the absorption of topically applied compounds (both physiological/pathological condition of the skin and physicochemical properties of the compound). The majority of reports for systemic toxicity have been from industrial chemicals/agrochemicals and occupationally these probably have the greatest potential hazard after dermal exposure.
