|The lungs and skin (as well as the nose and eyes) are the organs of first contact for most environmental exposures (excluding ingestion). This page complements other modes of learning about the skin's health in relation to occupational and environmental hazards.|
Relevant Fundamentals of Skin Structure and FunctionThe skin is not an absolutely impermeable membrane. It consists of a layer of horny dead cells overlying living (and very vulnerable) ones. It is fairly impermeable to water splashes but continuous immersion in water with friction will macerate it. Organic fat solvents can go through the skin fairly quickly.
Inorganic caustics (strongly alkaline compounds) will damage the skin very readily by sparifying fat and hydrolysing protein. The skin has a very good capacity to regenerate provided the deepest layers are not irretrievably damaged. However while it is still damaged and not yet fully healed it remains vulnerable to damage and can be made worse by many agents which the normal skin could easily have withstood.
Health effects on the skin
Acute corrosionObviously strong caustics, acids or similar substances will corrode the skin severely.
DermatitisBy far the commonest (but not the only) health effect on the skin from environmental agents is dermatitis (which can be considered synonymous with eczema) although this can also arise from non-environmental causes. Dermatitis simply means inflammation of the skin.
|Irritant dermatitis is caused by defatting agents (e.g. solvents, caustics), acids, or even salt(s) besides a variety of other substances. The image shows dermatitis in the hands of a cleaner in a hospital.|
can likewise be caused by a wide variety of agents e.g. rubber or many
substances used in its manufacture, several other plant products, dyes,
A very common cause of allergic dermatitis is nickel. The image shows dermatitis of the fingers from exposure to nickel in the keys of a clarinet. Note the cracked reddened skin.
|The presence of nickel in the metal (in this case in the keys of the clarinet) can be shown by testing. This is carried out with the reagent Dimethyl Glyoxime which results in a pink colour in the presence of Nickel ions (Ni++). The photos shows a positive test result on one of the metal parts of the instrument and a similar positive result on a twenty penny piece.|
UrticariaThis is another form of usually allergic skin disease, which is often termed hives or nettle rash. Occupational urticaria, when allergic is mediated by a type I mechanism like many instances of occupational asthma, with which it can coexist. For example latex or laboratory animal allergy can cause both asthma and urticaria, both as a result of sensitisation. This combination may be a herald of serious anaphylactic shock and angio-oedema. In some instances it is mediated by non-immune mechanisms, perhaps as a direct manifestation of mast cell activation.
AcneThis can be caused by exposure to dioxin(s) even in low concentrations, or chlorinated organic solvents or mineral oils if the exposure is high enough.
Other Toxic Effects
Vesicant effects (Blistering)Various other types of toxic effects can result from skin exposure to chemicals.
For example some substances with 'alkylating' properties e.g. 'mustard' compounds, and some alkyl organometallic compounds can produce severe blistering of the skin.
|The image shows blistering and inflammation of the hands
of an employee from skin contact with an alkylating compound used as a
drug in cancer treatment.
The way to avoid this sort of occurrence cannot simply be to 'ban' such hazardous substances since they in specific circumstances (such as cancer treatment) they have an important beneficial role. The answer must be in appropriate control at source, protection, education and work practice to ensure that occupational exposure to the skin or in other ways does not occur.
Disorders of PigmentationChemical agents such as para tertiary butyl phenol can cause a depigmentation called vitiligo. (This is because in their chemical structure they resemble the amino acid tyrosine which is a precursor of the skin pigment melanin.)
CancerSubstances containing polycyclic aromatic hydrocarbons, such as occur in pitch, tar and oil can cause skin cancer. This can also be caused environmentally or occupationally by inorganic compounds of arsenic.
References (this section is being revised):Information about the reported incidence of occupational skin disease in the UK and the Republic of Ireland is collected by EPIDERM and other surveillance schemes which are part of the THOR network at the University of Manchester.
Companion page on Occupational and Environmental Lung Disease