Epidemiology

The following is derived from the Health and Safety Executive (HSE) website:^[1]

• In 2004/05 there were 29,000 self-reported, work-related episodes of skin disease. In 2009/10, 22,000 such episodes were reported.
• An estimated average of 3,200 new cases of work-related skin disease were diagnosed each year between 2003 and 2005 by occupational health physicians. There were 2,455 cases of occupational skin disease reported by dermatologists and occupational physicians in 2009.
• Approximately 75% of these were contact dermatitis.^[2] Most of the remaining occupational skin diseases were skin cancers.
• There was a significant downward trend in the incidence of both contact dermatitis and other occupational skin diseases between 1996 and 2009.
• The annual number of workers with occupational dermatitis assessed as having some degree of disablement under the Industrial Injuries Scheme continued to fall from just over 400 in the early 1990s to 165 in 2004/2005.
• The occupations at highest risk in were:
  • Hairdressers and barbers.
  • Chemical and related process operatives.
  • Beauticians and related occupations.
  • Glass and ceramics process operatives.
• The most common agents cited by dermatologists and occupational physicians as causes of skin disease were:
  • Soaps and cleaning products.
  • Rubber chemicals and materials.
  • Working in a wet environment.

Mechanism of injury

Most insults can be classified as chemical, biological or physical in origin. Contact with allergens can arise from immersion of usually the hands but sometimes the legs. It may arise from direct handling of contaminated substances or from workbenches, tools or clothing. Splashing may occur or dust in the air, such as cement dust.

Chemical

More than 3,000 chemicals have been found to produce contact dermatitis in humans. They include acids, alkalis, water, salts of heavy metals, aldehydes, alcohol, esters, aromatic hydrocarbons, solvents and metallo-organic compounds.

Biological

Plants, animals, fungi, bacteria, arthropods and insects are amongst the offenders.

Physical

Heat, cold, variations in humidity, various wavelengths of light and ionising radiation can all damage skin.

Presentation

The presentation and pattern of skin change may give some indication of the likely irritant. Hands are the most frequently affected with direct contact. Chemicals on clothing may produce changes in axillae, groins and feet. Dust irritants are most likely to cause problems in areas where the dust might collect such as collar line, belt line and sock line or in flexural areas. Irritants in vapour or mist form are most likely to affect the face and neck. Both direct contact dermatitis and allergic dermatitis produce similar changes in the skin and may present with:

• Redness of skin.
• Vesicles or papules on an affected area.
• Crusting and scaling of skin.
• Itching of an affected area.
• Fissures (chronic exposure).
• Hyperpigmentation (chronic exposure).
• Pain or burning sensation from an affected area.

Differential diagnosis

Contact dermatitis can be very similar in appearance to endogenous eczema, and it is important to assess the distribution of the skin lesions when arriving at a diagnosis. Other problems to cause confusion include psoriasis and ringworm. Pre-existing skin disease does not exclude occupational dermatitis too; indeed, it may make the individual more susceptible.

Allergic and irritant contact dermatitis look identical.

Investigations

In most cases, no investigations will be required and the diagnosis is made on the clinical findings and history.

Skin patch testing is occasionally performed using standardised allergens. It must be carried out meticulously. Excessive concentration or dilution of a test patch may cause false positives or false negatives. It can help to distinguish between allergy, irritation and endogenous eczema.

Associated diseases

The following may result from contact with chemicals:

• Contact dermatitis.
• Contact urticaria.
• Acne, especially with oils.
• Pigmentary disorders.
• Skin cancer, usually squamous cell carcinoma, is more common than usually recognised.^[3]

Management

Nondrug

The most effective form of management is to avoid the irritant producing the dermatitis, when this has been identified. The use of protective gloves or clothing may be helpful depending on the irritant and the environment. Patients should be advised to wash their hands using products without perfume, and dry thoroughly afterwards. Rings should be removed, thoroughly cleaned and not worn again until the condition has resolved. Avoidance of the irritant may be the only treatment required in milder cases of recent origin; the dermatitis will then resolve in a period of approximately three weeks. Simple emollients may be used if the skin barrier has not been breached. The usefulness of barrier creams remains controversial.

Drugs

More severe or chronic forms of dermatitis will benefit from the use of topical corticosteroid cream, the strength and period of use of the steroid being adjusted according to the severity of the condition. The use of antihistamines may be helpful if itching of the affected area is a problem.

Second-line agents, eg psoralen combined with ultraviolet A (PUVA) treatment, ciclosporin and azathioprine may be initiated in a specialist setting for the treatment of chronic, steroid-resistant dermatitis.

Complications

Industrial skin disorders have a considerable adverse impact on the quality of life.^[4] They may also necessitate a change of occupation.

Prognosis

Usually, the condition will go with avoidance of the allergen but this may require giving up the job. A notable exception is cement dermatitis that is due to the chromium content. Even ceasing all contact with cement may not be enough and a nasty and severe dermatitis may persist.

Prevention

Employers have a duty to make the workplace as safe as possible. They may work in conjunction with trade union representatives to do so. They may seek help from the HSE or Committee on Substances Hazardous to Health (COSHH). The following checklist, abbreviated from the HSE, may be useful:^[5]

• Know what products or substances are being used or generated.
• Find the health and safety hazards associated with each substance or product. There may be product labels or Safety Data Sheets.
• Frequent contact with water (wet working) is a major cause of work-related disease (WRD). Some substances such as formaldehyde in metal working fluids, may be generated during work and can cause WRD.
• Who is exposed to these substances; how does their skin come into contact; for how long and the frequency?
• What control measures are in place?
• Is it possible to dispense with that chemical or to replace it with a safer one?
• Introduce safer ways of working to reduce contact.
• If the exposure is due to dust or vapour in the air, install a ventilated enclosure or provide local exhaust ventilation.
• Protective clothing may be worn. Selection of suitable gloves can be a complicated process and may require advice.
• Make sure employees have been educated about risk and avoidance.
• Provide mild skin cleaning cream and washing facilities with hot and cold water.
• Tell employees to clean their hands before consuming drinks and food or before wearing gloves.
• A management system must ensure than all controls are carried out.