Classification of irritant/ non-irritant and corrosive chemicals using excised human skin in vitro

Any chemical that is applied to the skin has the potential to induce a skin reaction. These reactions are complicated and are difficult to fully replicate in vitro and may exhibit species variations when reproduced in vivo. Skin irritation is the observed response (erythema, oedema, pain itching and heat) to chemicals that result in inflammation at the site of application. Skin irritation is defined as reversible damage of the skin following application of a chemical for up to 4 h. By contrast, skin corrosion is defined as ‘'irreversible damage to the skin, namely visible necrosis through the epidermis and into the dermis, following the application of a test substance for a period of 3 min up to 4 h”.