Occupational skin disease

Introduction

Occupational skin diseases are among the most common occupational diseases reported. For a skin disease to be considered occupational in origin, there must be a causal relationship between the occupation or work and the skin disease.

There are three broad groups of occupational skin disease:

1. Irritant contact dermatitis
2. Allergic contact dermatitis
3. Another occupational skin disease.

More than 90% of cases are classified as one or other form of contact dermatitis.

What occupations are most likely to be affected by skin disease?

The following occupations account for 80% of reported occupational skin disease in developed countries in Europe; most involve wet working conditions, which commonly results in contact dermatitis.

• Hairdressing/ beauty therapy
• Food industry
• Health care including dental and veterinary workers
• Laboratory workers, including scientists and laboratory technicians
• Agriculture including farmers, gardeners and florists
• Cleaning
• Painting and decorating
• Motor vehicle repair
• Construction work
• Printing
• Homemakers

Other occupations reviewed on DermNetNZ include:

• Textile workers
• Boatbuilders
• Chemical workers.

The sites affected by occupational skin disease depend on exposure. About 80% of patients with occupational skin disease present with hand dermatitis.

Younger workers have a slightly higher risk that older workers, but who are affected will depend on:

• Individual predisposition – particularly atopic dermatitis/eczema or sensitive skin
• Personal hygiene
• Circumstances of exposure.

Irritant contact dermatitis

Irritant contact dermatitis occurs when contact with chemical or physical agents injure the skin’s surface faster than it is able to repair the damage. Occupational irritant contact dermatitis:

• Comprises about 80% of all occupational skin diseases
• Includes chemical burns and most cases of contact urticaria
• Chronic cumulative irritation is often diagnosed by exclusion of an allergic cause for dermatitis, but it may co-exist with allergic contact dermatitis.

Clinical features of irritant contact dermatitis are varied.

• It may be a single episode that recovers, repeated relapsing episodes, or chronic dermatitis due to repetitive injury.
• In general, the degree of damage following irritant exposure depends on the potency of the irritant, the duration of application, the frequency of exposure, occlusion, temperature, anatomical site, and individual susceptibility.
• Where there is repeated exposure, previous damage may render the skin more susceptible to damage from the next exposure. However, hardening may also occur.
• Because contact irritant dermatitis is dose-dependent, it tends to be restricted to the site of primary contact, which is usually the hands. A reduction in the cumulative exposure to irritants lessens the risk of dermatitis. Conversely, occlusion of the irritating chemical(s) or particulates by gloves, jewellery (such as wedding rings), or wristwatch can aggravate dermatitis.
• Dermatitis may be dry, flaking, and fissuring; or erythematous, swollen, blistering, weeping and eroded.
• Broken skin leads to a risk of skin infection (impetigo), presenting as red, painful, swollen skin with ulceration, oozing or pustules.

Allergic contact dermatitis

Allergic contact dermatitis is an immunological response (allergy) to a contact allergen. Only people who are allergic to a specific agent (the allergen) will show symptoms. The appearance can be exactly the same as irritant contact dermatitis. Allergic contact dermatitis:

• Comprises > 10% of occupational skin disease
• Includes protein contact dermatitis e.g. in foods
• The incidence rate is reported to be increasing.

There are some specific features of allergic contact dermatitis:

• The allergen may have been previously tolerated for years without causing dermatitis.
• Once sensitised the reaction may occur with minimal exposure to the allergen.
• Dermatitis may occur not only at the site of primary contact, but also at secondary sites eg a person who is allergic to an epoxy chemical may not only get dermatitis on their hands, but also dermatitis on the face or genitals, where they transferred tiny amounts of allergen by accident with their fingertips.
• Dermatitis occurs within hours or days of exposure to the allergen.
• Symptoms settle down when the skin is no longer in contact with the allergen, although this may take weeks and require treatment.
• Allergic contact dermatitis can usually be confirmed by patch tests.

Other occupational skin diseases

Skin conditions other than dermatitis may occur as a result of occupational exposures. These comprise <10% of occupational skin disease.

• Skin cancer is more likely in some occupations. In a Finnish report [1],11% of deaths caused by melanoma and squamous cell carcinoma can be attributed to work exposure, for example in roof tilers and bricklayers.
• Certain skin infections are more common in particular workers.
• Basal cell carcinomas may occur at sites of injury such as welding burns.
• Scleroderma, leukoderma, onycholysis and miliaria are amongst the numerous other skin and nail conditions that may occur as a result of occupational exposures.

What are the main types of occupational exposure?

Occupational skin disease may follow exposure to chemical, biological or physical agents.

Chemical exposure

• Numerous chemicals including rubber additives, hair dyes, preservatives, epoxy resins and acrylates can cause contact allergic dermatitis.
• Vinyl chloride exposure has been implicated in scleroderma; silica and solvent exposure have also been linked to scleroderma although this is more controversial.
• Tar and arsenic have been associated with skin cancer
• Oils may cause folliculitis.
• Catechols and phenols may cause depigmentation (leukoderma)
• Cement under occlusion can cause a chemical burn

Biological exposure

• Contact with animals may result in infections such as orf (from sheep and goats), milker’s nodules (from cows) and tinea corporis / ringworm (from horses, cattle, pigs, cats and dogs).
• Contact with infected/infested humans may result in infections such as impetigo and tinea corporis /ringworm and infestations such as scabies and head lice.
• Contact with aquatic life may result in marine wounds and stings from jellyfish and sea urchins, erysipeloid and atypical mycobacterial infection from fish.
• Contact with insects may result in contact urticaria from caterpillars and cockroaches, and arthropod-borne viral skin infections or protozoa infections.
• Contact with plants may result in urticaria from nettles, and allergic contact plant dermatitis from sap from cut stems of daffodils, dahlias, chrysanthemums, and Peruvian lilies and wood resins.

Physical exposure

• Mechanical trauma to the skin leads to cuts, blisters, calluses, blood clots, and basal cell carcinoma may arise in thermal burn and other scars.
• Vibration from vibrating tools may provoke a vibration white finger (Raynaud phenomenon).
• Direct heat causes thermal burns.
• Hot humid environments may provoke acne, sweat rash (miliaria), intertrigo (chafing), skin maceration and supervening bacterial infection or fungal infection.
• Low humidity environments may result in chapping and fissures.
• Cold environments cause frostbite, chilblains, cold urticaria, Raynaud phenomenon.
• Ultraviolet radiation is the main cause of skin cancer and photoageing.
• Ionising radiation (X-rays, α, β, and γ rays) may cause radiation dermatitis and radiation-induced skin cancer.
• Physical irritants such as particulates, rough surfaces, and fibres (eg fibreglass) may cause irritant dermatitis.
• Dermal penetration may introduce poison or infection leading to skin necrosis (skin destruction).

How can occupational skin disease be prevented?