Dermal Absorption

Lindsay Pasquale

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Dermal Absorption

 Dermal absorption describes the transportation of chemicals from the outer surface of the skin both into the skin and into the systematic circulation according to the World Health Organization (WHO). Exposure of chemicals can occur from occupational, environmental, or consumer, which then can lead to diseases, disorders or death. The skin can absorb chemicals without the worker even knowing. Skin absorption occurs in the process of diffusion, where molecules spread from areas of high concentration to areas of low concentration.

 Contact dermatitis is one of the most common types of occupational illness, with an estimates annual costs exceeding $1 billion as stated by CDC. Four causes Occupation Skin Disease (OSD) include mechanical trauma, biological agents, chemical agents, and physical agents. Chemical agents are the main cause of occupational skin diseases and disorders. The agents are divided into two different types; primary irritants and sensitizers. Primary irritants act directly on the skin, while sensitizers may not cause immediate skin reaction. A person may be exposed through direct contact with contaminated surface, deposition of aerosols, or splashes. Physical agents include extreme temperature either hot or cold, and radiation such as UV or solar radiation. Mechanical trauma would be friction, pressure, abrasions, cuts or bruises. Lastly, biological agents include microorganisms, parasites, plants and animal materials.  

 CDC estimated that more than 13 million workers in the United States are potentially exposed to chemicals that can be absorbed through the skin. The skin is the largest organ of the body and protects us from microbes and the elements. It is also very important because it helps regulate body temperature. The skin has three layers; the epidermis, dermis, and hypodermis.

 The rate of penetration is related to the lipophilicity of the chemical. Lipophilic is the tending to combine with or capable of dissolving lipids. The more lipophilic a chemical, the greater its rate of penetration. Lipophilicity and hydrophilicity refer to the solubility of something in water or lipids. On the other hand, lipophilic substances tend to be non-polar, and hydrophilic substances tend to be polar.

 Not everything people touch is absorbed into their skin and bodies. Skin penetration represents the amount of a chemical that exists between the stratum corneum and the stratum basale. During the process the body does not yet absorb the chemical, and it doesn’t affect the body systems. Skin absorption occurs when the chemical breaks the skin barrier to reach the bloodstream. It can go two different routes, the chemical can leave the person through bodily fluids, or build up, also known as bioaccumulation.

 Different areas of your body absorb at a different rate of speed. A person’s scalp is the most absorbing area of the body. I personally use multiple hair products and dye my hair quite frequently. I never thought about whether it could be harmful to my body. When I get my hair done, the smell of the dye is incredibly strong and even leave a burning sensation while it sits and processes. It makes me wonder what I’m really absorbing in my scalp.

https://www.cdc.gov/niosh/topics/skin/ 

http://www.who.int/ipcs/publications/ehc/ehc235.pdf?ua=1
http://www.who.int/ipcs/features/2006/ehc235/en/