Contact Dermatitis in Construction: Risks, Types & Irish Law

Introduction and Scope

The purpose of this literature review is to provide a medical epidemiological overview of contact dermatitis, with a focus on the risks and complications associated with contact dermatitis among workers in the construction industry, and with attention to Irish laws designed to protect workers from exposure to irritants that may result in contact or allergic contact dermatitis.

Much of the prior research has focused on irritant contact dermatitis (ICD), a condition known to cause symptoms ranging from redness, inflammation, and itching to the development of sores and blisters on the skin (Hogan & May, 2007; CCOHS, 1997; Goldner, 1994; Royal College of Physicians, 1995). Prolonged exposure to a substance may lead to a process known as "sensitization," which increases an individual's likelihood of developing allergic contact dermatitis — a less commonly studied but increasingly prevalent form of contact dermatitis that may affect an individual for a lifetime (Hogan & May, 2007; Goldner, 1994). Health care agencies have long recognized that certain populations are at greater risk for developing allergic contact dermatitis than others, including individuals working in the construction industry (Royal College of Physicians, 2005).

The questions this literature review addresses include: (1) defining what contact dermatitis is; (2) distinguishing the differences between allergic contact dermatitis and irritant contact dermatitis; (3) assessing the level of protections provided to workers against contact dermatitis; (4) reviewing Irish law and its relevance to allergic and irritant contact dermatitis among the public and construction workers; and (5) examining efforts within the construction industry aimed at reducing the risk of developing allergic contact dermatitis through adequate training, protection, and review of hazardous working conditions. A comprehensive review of scientific and governmental literature is provided to address each of these questions.

The purpose of this investigation is to determine the prevalence of contact dermatitis and to identify what actions may be necessary to mitigate risk or provide additional resources for those most at risk for this condition.

As more and more construction workers develop symptoms of allergic contact dermatitis, it is increasingly important that researchers focus on ways to prevent occupational hazards from reducing workers' capacity to work or their quality of life. Among the important facts noted in the literature is the increasing prevalence of contact dermatitis in Ireland and other areas where legislation has been slow to enforce occupational health acts that would protect workers from exposure to chemical irritants. Cases cited in this review suggest that Irish buildings and drinking water are among the primary causes of allergic or irritant contact dermatitis among workers and civilians alike. This underscores the need for a thorough review of contact dermatitis in its many forms, and an evaluation of current legislation to assess whether it is adequate to protect workers from developing debilitating forms of this condition.

Allergic Contact Dermatitis: Definition, Pathophysiology, and Prevalence

Multiple studies suggest that the prevalence of allergic contact dermatitis is on the rise, especially within the European Union and Ireland, where federal regulations are in place but not necessarily strictly enforced to provide workers adequate protections against risk factors leading to the development of allergic contact dermatitis (Royal College of Physicians, 2005; Hogan & May, 2007; Cohen & Cohen, 1998). When examining contact dermatitis, it is important to distinguish between the types most likely to affect construction workers. This literature review therefore focuses on both allergic contact dermatitis — a currently understudied phenomenon — and irritant contact dermatitis, the two forms of contact dermatitis most prevalent in the construction, house-building, and related industries (Cohen & Cohen, 1998).

There is ample evidence suggesting that many do not distinguish between allergic and irritant contact dermatitis. While the two conditions are related, it is important to differentiate between them because allergic contact dermatitis may prove more damaging to an individual in the long term, reducing quality of health and increasing sensitization and immune response to other toxins encountered in the industry (Cohen & Cohen, 1998, p. 4).

Allergic contact dermatitis (ACD) is not the same as contact dermatitis resulting from exposure to a common irritant. Rather, ACD results when a person has a specific sensitivity to a known substance and develops delayed-onset allergic symptoms (Hogan & May, 2007). Many people mistakenly conflate allergic contact dermatitis with irritant contact dermatitis (ICD), which results from damage caused by a chemical that would harm anyone's skin regardless of whether they had a known sensitivity to that chemical or agent.

ACD was first identified by researcher Jadassohn, who used a "patch test" to identify chemicals he was allergic to; this work led to the later development and popularity of patch testing (Hogan & May, 2007; Larkin & Rietschel, 1998). Over time researchers developed a modern version of this test, now known as the "thin-layer rapid use epicutaneous" or "TRUE" test (Hogan & May, 2007, p. 1). A common example of a delayed-onset ACD case is a healthcare worker who becomes allergic or sensitive to latex, a substance frequently used in healthcare and other work settings.

Certain chemicals are recognized as common triggers for ACD. Cytokines play an important role in evaluating allergic contact dermatitis because they are responsible for regulating intercellular adhesion molecules, including interleukin-8 (Hogan & May, 2007, p. 1).

According to the National Health and Nutrition Examination Survey (NHANES), just under 14 per 1,000 people are diagnosed with ACD, with roughly 8 million people visiting their doctor annually for a confirmed diagnosis of allergic contact dermatitis (Hogan & May, 2007; Larkin & Rietschel, 1998). In other countries, dermatitis is equally or more common. A Dutch study suggested that 12 of every 1,000 people would develop some form of ACD during their lives, whereas in Sweden fewer than 3 per 1,000 succumb to ACD (Hogan & May, 2007, p. 1). McFadden & Basketter (2000) note that within Europe and Ireland there are many cases in which construction workers developed allergic contact dermatitis due to pre-existing chemicals and toxins in older buildings and from exposure to unsanitary conditions resulting from lax labor laws meant to protect employees.

Pathologically, many people with ACD will develop symptoms several days following exposure to the allergen, making diagnosis sometimes difficult. Others may not react severely on first contact with a potential allergen but may react more severely with frequent exposure (Hogan & May, 2007).

Cohen & Cohen (1998) describe erythema multiforme, one of many reactions associated with allergic contact dermatitis, which results in hypersensitivity occurring shortly after exposure to an allergen or infection. The researchers note that while erythema multiforme may result from an allergy to nickel and other common allergens, there is only one report of findings suggesting it occurs following Rhus contact dermatitis (p. 140). This illustrates how much remains to be learned about allergic contact dermatitis and the likelihood that sensitivity to certain substances will produce more or less severe reactions upon single or prolonged exposure.

In a retrospective study of 732 patients referred for patch testing, Cohen et al. (1997) found that patch testing is a valid and useful tool for defining an individual's allergies and assessing the likelihood and severity of contact dermatitis in the workplace and other environments (p. 916). Of the patients examined, roughly half experienced positive reactions deemed clinically relevant. The researchers suggested that 20 allergens are most likely to cause allergic contact dermatitis within the United States, and that the patch test alone is a limited tool, though helpful when combined with other testing methods in assessing one's risk factors for contracting allergic contact dermatitis.

The Canadian Centre for Occupational Health and Safety (CCOHS, 1997) defines allergic contact dermatitis — often referring to it as "occupational contact dermatitis" — as a primary cause of local inflammation of the skin with accompanying pain, redness, and formation of blisters (p. 1). According to the CCOHS, allergic contact dermatitis often develops in stages: a construction worker or other worker may be exposed daily to allergens that do not immediately cause a skin reaction.

The CCOHS notes that allergic reactions including inflammation, redness, and blister formation may appear only after prolonged exposure to potential allergens. For some individuals this may mean a few days of exposure before symptoms arise; for others, exposure over a lifetime may produce only minor dermatitis (CCOHS, 1997). Typically, sensitization to a compound occurs first, followed by penetration of the epidermal layer of the skin and an allergic reaction — a process that can take up to four weeks (CCOHS, 1997).

This process occurs when allergenic compounds bind to proteins naturally present in the skin, and lymphocytes within the body react to protect the skin from damage. Tissue-damaging chemicals called "lymphokines" may be released, ultimately producing the symptoms commonly associated with allergic contact dermatitis: pain, swelling, redness, and the formation of blisters (CCOHS, 1997, p. 1). Pre-existing irritant contact dermatitis may increase the prevalence of allergic contact dermatitis, as can cuts or other breaks in the skin that allow faster penetration of allergenic compounds (McFadden & Basketter, 2000). Penetration of the epidermal layer is necessary for ACD symptoms to occur, as it leads to the binding of toxic substances to lymphocytes, triggering the outbreak of redness, swelling, or blisters (McFadden & Basketter, 2000).

Those most at risk include cabinet makers, carpenters, construction and automobile workers, agricultural workers, and any workers who handle substances requiring the use of latex gloves or involving exposure to chromates, rubber, resins, cobalt, cement, chromium, formaldehyde, or certain woods (CCOHS, 1997, p. 1).

The Royal College of Physicians (2005) and other international organizations, including the EPA in Ireland, are working to develop legislation focused on the potential causes and risk factors for allergic contact dermatitis among construction workers and manufacturers that may produce substances containing toxic agents that lead to sensitization. Allergic contact dermatitis is more likely to occur in workers chronically exposed to a known irritant, in those who develop even a single case of ICD, and in individuals with hereditary risk factors such as a family history of allergies (Choi, Lee & Cho, 2000, p. 44).

It is important to note that research on irritant contact dermatitis frequently suggests that allergic contact dermatitis is more likely to manifest when an individual who has developed a single case of irritant contact dermatitis is subsequently exposed to a compound. While ICD typically manifests with a faster onset than ACD, its symptoms are nearly identical in many cases, and the mechanisms by which it develops in the body are also similar (Choi, Lee & Cho, 2000, p. 45).

Apart from allergic and irritant contact dermatitis, other forms of dermatitis may coincide with or occur separately from these conditions. These include atopic dermatitis, or eczema, which more commonly results from hereditary causes and increases the likelihood that an individual may become sensitized to a chemical or compound, resulting in allergic contact dermatitis (Choi, Lee & Cho, 2000, p. 45).

Irritant Contact Dermatitis: Characteristics and Diagnosis

More literature is available on irritant contact dermatitis than on allergic contact dermatitis; however, the research on ICD can be correlated with that of ACD, since irritant dermatitis may be a risk factor for or cause of the development of allergic dermatitis (McFadden & Basketter, 2000).

Chronic irritant contact dermatitis is characterized by inflammation of the epidermal cells of the skin, resulting in redness (erythema), some swelling, and at times scaling of the skin (Choi, Lee & Cho, 2000; McFadden & Basketter, 2000). Less is known about ICD than about allergic dermatitis, in part because there are few precise diagnostic tests currently available for evaluating and properly diagnosing this form of contact dermatitis (Sarkis, 2000). Typically, to diagnose ICD a healthcare worker must rule out other cutaneous diseases including allergic contact dermatitis, and base the diagnosis on the clinical appearance of the dermatitis and the patient's documented exposure to a potential irritant (Sarkis, 2000; Goldner, 1994).

The pathophysiology of ICD involves inflammation arising from the release of cytokines from epithelial cells, typically triggered by contact with a chemical agent (Sarkis, 2000). Three primary changes are observed in patients with ICD: skin barrier disruption, in which the irritant penetrates the skin; cellular changes within the epidermal layer; and cytokine release (Sarkis, 2000, p. 2). Common irritants include detergents; eczema arising from exposure to cleaning agents is a frequently cited example of ICD (Sarkis, 2000).

Prolonged exposure to any toxic chemical will result in sensitization and subsequent disease manifestation, as is the case with ICD. Researchers also note that stimuli other than chemical agents — such as exposure to environmental hazards including ultraviolet light in the case of outdoor workers — may exacerbate the condition (Sarkis, 2000).

Hogan & May (2007) note that ACD is a leading occupational hazard and illness, with most affected individuals demonstrating symptoms in their hands or from eye exposure (Lawley & Kubota, 1991, p. 265). This is one reason why preventive care and proper training are important for individuals at risk of developing dermatitis from chronic exposure to chemical or other known irritants or allergens. Among the forms of contact dermatitis most prevalent among construction workers are those affecting the hands, eyes, lungs, head, and neck; preservatives and formaldehydes are often implicated (Diepgen & Coenraads, 1999, p. 500).