Contact dermatitis is a type of skin inflammation that happens when a substance touches the skin, leading to irritation. This irritation may result from an allergic reaction or, more commonly, from direct irritation by the substance.
It is most common in occupations such as hairdressing, food handling, nursing, cleaning, plant operation, construction, general labour and mechanics.
In addition to causing pain or discomfort, dermatitis can sometimes lead to extended time off work. In some instances, individuals may be unable to return to the same job because they have become sensitised to the substance.
Skin reaction
Areas of irritated skin may be red, swollen, tender, hot, painful or itchy. If the reaction is severe, the skin may blister, weep, and become crusty. There may be some scaling as the skin heals.
Skin affected by dermatitis for several weeks tends to thicken and darken in colour. Sometimes there may be a reaction only when direct sunlight and an irritating substance are on the skin at the same time. This kind of contact dermatitis looks a lot like sunburn. Scratching or rubbing itchy skin can worsen dermatitis symptoms.
Substances that can cause contact dermatitis
Many of the chemicals used in industry can cause a sudden, very strong irritant or corrosive reaction when they come into contact with bare skin. Safe work systems should be developed for such substances as:
- acids
- alkalis
- oils
- solvents
- petroleum products.
Wet work, sweating, heat, dust, friction and prolonged glove use may also cause or contribute to irritant contact dermatitis. Some products that may cause allergic contact dermatitis are:
- cement (due to traces of hexavalent chromium)
- powdered latex gloves
- synthetic rubber (may have traces of thiurams, dithiocarbamates, diphenylguanidine or thioureas)
plastics - fibreglass
- epoxy resins (used in flooring, marine paint and adhesives)
- acrylates used in dentistry or in artificial nails
- isocyanates (found in 2-pack vehicle paints and in foam manufacturing)
- hair dyes (even if labelled “natural” or “organic”, they may contain paraphenylenediamine (PPD) or toluene-2,5-diamine sulphate which are allergenic)
- hair bleach (e.g., ammonium persulphate)
- tattoos (e.g. “henna” tattoos which may contain PPD)
- glue
- hand wash (may contain traces of coconut diethanolamide, lanolin, fragrance, cocamidopropylbetaine or chlorhexidine)
- preservatives (e.g. methylchloroisothiazolinone, methylisothiazolinone, chloroacetamide, formalin or iodopropynyl butylcarbamate)
- shellfish
- metal objects with nickel or chromium content.
Natural plant and animal products may cause a skin reaction in some people. Sawdust from certain wood varieties and natural oils used in perfume are among the plant products that may cause a reaction.
Sometimes the skin may be affected by chemicals used to process natural products, such as the dyes in leather, fur, wool and cotton and preservatives in cosmetics, creams and ointments.
Different people will react differently to each substance, and some workers may not be affected by any of them at all.
How long after contact will dermatitis develop?
Some irritating substances will have an immediate and obvious effect on the skin. Other substances could be used regularly for a long time before the skin begins to react. After the first reaction occurs, dermatitis will develop fairly quickly with each subsequent exposure to that substance.
Preventing contact dermatitis
Persons conducting a business or undertaking (PCBUs) are required by work health and safety legislation to eliminate risks to health and safety so far as reasonably practicable or otherwise to reduce risks so far as reasonably practicable. Specific actions to reduce risk include:
- provide safety data sheets for hazardous chemicals
- substitute a safer alternative substance or product. For example, replace powdered latex gloves with unpowdered latex gloves or disposable nitrile gloves
- include information about contact dermatitis in your safety training programme
- keep the work area clean
- provide personal protective equipment (PPE) and barrier creams where appropriate
- take additional precautions for workers with known allergies.
Workers are required by law to protect themselves by following the PCBU’s safe work practices and by using the provided PPE.
Wash your hands with a mild soap and water, and then dry them thoroughly after work. Use a cleanser made from vegetable oil to remove grease or other substances that will not come off with soap and water. Some barrier creams applied before work may make it easier to remove substances that tend to stick to the skin or provide some protection from wet work.
- Do not use solvents such as kerosene or turpentine to clean hands
- Do not use barrier cream on damaged skin
- Treat minor cuts and abrasions promptly.
If you suspect that you have contact dermatitis, see your doctor. Early treatment is important for the best results. Speak with your health and safety representative and PCBU about how to overcome the problem and make the workplace safe.