The Skin

2/28/2011

Our skin is a lot more complicated than many of us might expect.  After all, it can range in thickness from less than 0.1 millimeters to greater than a centimeter, depending on the specific area (as well as your chosen occupation) while consisting of multiple layers: each layer designed to perform very specific functions.  And while it has an average area of 2 square meters (if one were to peel his/her skin off and lay it on the floor – don’t try this at home folks!), it contains over two million sweat glands and provides protection from the sun’s ultra-violet radiation. Our skin also regulates our internal body temperature even when we are subjected to extreme cold (see the recent SafetyShare on Cold Stress) or heat. 

Our skin plays an important role in the protection from outside contaminants, as it serves as our first line of defense from outside invaders. Normally dry, it provides a poor environment for microorganisms to live and accumulate – at the same time providing a physical as well as reactive barrier to many chemical contaminants; thereby stopping such substances from entering into our bodies and causing serious harm.

Unfortunately, some materials, such as organic solvents and pesticides can be absorbed through the skin causing both immediate dermal dysfunctions and disturbances, while allowing systemic reactions, resulting to damage to internal biologic systems such as the liver and kidneys.  This occurs when certain chemicals, after being absorbed into the skin, enter the blood stream where they can be transported throughout the body, residing in specific organs that are susceptible to the specific chemical. Therefore, when dealing with chemicals and other contaminants, we need to apply the appropriate personal protective equipment (PPE), such as gloves, coveralls or aprons.  It is important to understand what the specific contaminants of concern may be as certain PPE materials may not be effective in stopping a chemical from contacting the skin; thereby resulting in an occupational illness. For instance, depending on the manufacturer, typical nitrile gloves are not designed to protect against aromatic hydrocarbons such as benzene and toluene, but can serve well against acetic acid, hydrochloric acid and cyclohexane (a better material for protection against benzene and toluene would be polyvinyl alcohol gloves). Therefore, prescribing the right PPE requires some research in which your safety and health professional can offer assistance.

Considering contact with such work hazards as chemicals, physical aberrations, and biologic risks (contact with poisonous plants and animals), the United States Bureau of Labor and Statistics has gathered data showing that 13% of occupational injuries and illness are skin-related. In addition, skin-related occupational incidents account for one of the highest causes of lost work days; thus being very costly as projects may be impeded and administration of medical attention.   

The skin has three main layers: the epidermis (outer layer), dermis (middle layer), and subcutaneous (inner layer).  Each serves very specific functions.   

The epidermis can be further divided into the stratum corneum and germinative layers. It is the stratum corneum that offers the first line of defense from chemicals and other contact contaminants, as cells (keratinocytes) in this layer are designed to slough off, thereby removing the chemical/contaminant while being replaced by new cells that are formed in the germinative layer.  The epidermis also contains melanocytes: pigment-forming cells that protect us from UV radiation, which has been associated with the destruction of DNA and causing skin cancer.  Chemicals such as phenols and other organic solvents have been known to destroy melanocytes (as well as the protective pigment, melanin), thereby, not only being a potential for dermatitis, but also leaving us susceptible to more serious conditions. 

Langerhan’s cells, also located in the epidermis, are responsible for antigen recognition and therefore play a vital role in thwarting allergic reactions as these cells protect us from substances that are responsible for contact dermatitis.     

The next skin layer, the dermis (or dermal layer) contains blood vessels, nerve endings and repair tissue.  When we receive a serious cut/laceration, it is the dermal layer that responds and places a permanent cover on the wound: unfortunately, this usually results in a scar.   Because blood vessels are located in this layer, we can understand when certain chemicals penetrate the initial top layer (epidermis), they enter into the dermis, and can potentially enter our circulatory system and travel throughout our body making contact with our internal organs. 

The inner skin layer, the subcutaneous layer, contains fatty tissue that acts as insulation.  This layer also contains our sweat glands while connecting the skin with body muscle and bone. It is noteworthy to mention that typical third degree burns (the most severe type) affect the subcutaneous layer.  Because the nerve endings located in the middle layer have been destroyed, many times, victims of severe burns, initially do not feel any pain and may not even know how badly they have been hurt.  

Without a doubt, our skin is complicated. It contains so many different cell-types and performs so many functions.  Damage to our skin can present some serious health problems.  Some initiating from chemicals, others from the sun, or from fires, burns, cuts as well as contact with allergens (plants, animals, etc.).  But we do have the means by which to properly protect ourselves. The first step is to recognize the potential hazard and then to develop the proper controls. These controls may be using a hot work permit (to protect us from burns), use of sun screen or working in a shady area or wearing a hat (especially for follicle-challenged individuals) or wearing the right PPE.  Your Safety and Health professional is ready to assist.    

Safety Tip: Protect your hands; you need them to pick up your pay check

When life gives you a hundred reasons to cry, show life that you have a thousand reasons to smile (Unknown Author)