Understanding percutaneous absorption for occupational health and safety.

Local and systemic toxicity from percutaneous absorption depends on a chemical's penetrating the skin, which is both a barrier to absorption and a primary route to the systemic circulation. The skin's barrier properties are such that fluids and precious chemicals are reasonably retained within the body, while foreign chemicals are restricted from entering the systemic circulation. The skin is a primary body contact with the environment and the route by which many chemicals enter the body. In most instances, the toxicity of the chemical is slight and/or its bioavailability is too low to cause an immediate response. However, some chemicals are toxic when applied to the skin, and more chemicals that come in contact with the skin are being found to be potentially toxic. This article describes percutaneous absorption, methods to determine it, and factors that can affect it.