Occupational dermatoses are any abnormal conditions of the skin caused or aggravated by substances or processes associated with the work environment. Occupational skin diseases (OSDs) are a major public health problem because they are common, are often chronic, and have significant economic impact on society and on workers.1 A thorough knowledge of potential irritants, allergens, and other causative factors in the workplace, as well as the workers’ compensation system, is essential for the dermatologist dealing with occupational dermatoses.

 Paracelsus (1498–1541), in his Morbis Metallicus, was the first to write about OSD, including changes in the skin caused by salt compounds. Agricola described deep skin ulcers in his book about metalworkers at the same time. Ramazzini (1700), the father of modern occupational medicine, made observations about OSD in his classical work De Morbis Artificium Diatriba. Sir Percival Pott (1775) described carcinoma of the scrotum among chimney sweeps; at the same time other authors described and studied OSD and contact dermatitis. Earlier texts include Prosser White’s The Dermatergoses or Occupational Afflictions of the Skin (1915), and Schwartz, Tulipan, and Birmingham’s Occupational Diseases of the Skin (1957). Selected current resources for more in-depth information are listed in eTable 211-0.1.

The US Department of Labor publishes annual incidence statistics on the safety and health of employees in private industry (http://www.bls.gov/). In 2008, of the 3.8 million nonfatal job related injuries and illnesses reported among the private industry establishments, 5.1% (193,800 cases) were work-related illnesses, of these, skin disorders were the second most common reported illness, accounting for almost 38,000 cases.2 Occupational contact dermatitis is the most commonly reported OSD, and in most countries, the reported incidence of occupational contact dermatitis varies from 5 to 19 cases per 10,000 full-time workers per year.3 Incidence rates also vary based on the specialty of the reporting physicians; rates are six to eight times higher in some studies when cases are reported by occupational physicians rather than by dermatologists.4

The number of OSD cases has declined,5 especially in the past 8 years, possibly due to better prevention, the ease with which workers’ compensation cases are accepted, and a change in reporting patterns of employees or employers.6 However, a large number of minor or transient cases still go unreported or untreated, so the exact incidence is not known. Occupational skin disease still accounts for a significant percentage of days away from work. In 2008, dermatitis led to 3,170 (8.4%) of the skin disease cases resulting in days away from work and 2,630 (83%) of these cases were caused by contact dermatitis.2

Distribution of nonfatal occupational injury and illness cases by category is demonstrated in Figure 211-1. Surface wounds and bruises and trauma-induced injuries are not considered among the skin disease and illnesses. Surface wounds and bruises accounted for 11,2870 (12.24%) of all traumatic injuries and disorders cases involving days away from work in 2008.7

(See Chapter 48.)

Irritant contact dermatitis (ICD) is a nonimmunologic inflammatory reaction of the skin to contact with a chemical, physical, or biologic agent. ICD is the most common OSD, accounting for up to 80% of cases, although some authors have found a relatively equal distribution of ICD and allergic contact dermatitis (ACD).3Chapter 48 discusses ICD in detail. Exogenous and endogenous factors influencing ICD are listed in Tables 48-1 and 48-2. In addition to the more common acute and chronic eczematous reactions, the clinical spectrum of ICD includes ulceration, folliculitis, acneiform eruptions, miliaria, pigmentary alterations, alopecia, contact urticaria, and granulomatous reactions (Table 211-1).8

Major Categories of Irritant Contact Dermatitis

The two major types of occupational ICD are acute ICD and cumulative ICD. These and the many other subtypes are discussed in Table 48-3, which summarizes their time onset and prognosis.

Acute Irritant Contact Dermatitis, Including Chemical Burns

Acute eczematous dermatitis after exposure to a potent irritant, often an acid or alkali, may overlap with chemical burns. Highly irritating chemicals may induce a reaction in anyone if the concentration and duration of action are sufficient. The intrinsic nature of the chemical is also important. Common irritants in the workplace are discussed in Common Occupational Irritants later in the chapter. In national statistics for work-related injuries, acute ICD reactions are often classified as chemical burns (Fig. 211-2).

Cumulative Irritant Contact Dermatitis

Cumulative ICD, the most common type of ICD, develops slowly after multiple subthreshold exposures to mild irritants (soap, water, detergents, industrial cleansers, solvents, etc.) under a variety of conditions.9 Some of the high-risk occupations for ICD are listed in Table 211-2. For a comprehensive list, see the sources presented in eTable 211-0.1. The other categories of ICD, as well as predisposing factors, including exogenous as well as endogenous factors, are discussed in Chapter 48. Atopic individuals have an increased susceptibility to skin irritation and account for a large percentage of workers’ compensation dermatitis claims.

Low-Humidity Dermatitis

Workers, especially atopic individuals who are subjected to low relative humidity at work (Table 211-3),10 are also at risk for developing dermatitis, especially with the presence of other irritants. When relative humidity is below 35%–40%, the stratum corneum becomes drier and more brittle, and shows increasing permeability to marginal irritants. Symptoms such as pruritus and burning may be the only complaints and are more distressing than physical signs, which may involve exposed or covered areas. Differential diagnosis includes irritation from airborne substances, other dermatoses, and psychogenic causes.

Airborne Irritant Dermatitis

Airborne irritants are an important cause of contact dermatitis. The pattern is fairly characteristic, with subjective symptoms of stinging, burning, or smarting sensations. Objective findings range from barely visible diffuse lesions to more severe dermatitis of the eyelids, cheeks, nasal folds, and neck. Some airborne irritant particles cause symptoms only if occluded under clothing in the flexures and other intertriginous body areas.

The most frequent causes are irritating dusts and volatile chemicals, such as solvents, ammonia, formaldehyde, epoxy resins and their hardeners, cement dust, fibrous glass, and sawdust, especially from irritating woods.11 See Table 48-4 for a list of other airborne irritants.

Diagnosis of Irritant Contact Dermatitis

The diagnosis of ICD is based on a history of exposure to a known potential irritant, the clinical appearance, and the distribution of lesions.12 Subacute and chronic irritant dermatitis are almost always diagnoses of exclusion. Patch testing (see Chapter 13) helps to distinguish ACD from ICD or to diagnose a superimposed ACD or ICD. More detailed criteria for the clinical diagnosis of ICD are discussed in Chapter 48 and especially Box 48-1 and Table 48-7.

Common Occupational Irritants

Soaps and Detergents

Soaps and detergents are weak skin irritants; however, excessive use can cause cumulative insult dermatitis in susceptible individuals. The choice of cleanser varies with the job for which it is intended; for example, machinists and auto mechanics need a cleanser with a high detergent and abrasive action. The inappropriate use of products intended as industrial cleansers can also result in dermatitis.

Waterless Hand Cleaners

Waterless hand cleaners are formulated to remove tough oil and grease stains and are widely used at work sites where there is no convenient source of water. They should be applied sparingly because they may contain petroleum-derived solvents and may result in dermatitis if overused. Instant hand sanitizers, which often contain high concentrations of alcohol, can be drying to the skin.

Acids and Alkalis, Including Chemicals that Cause Burns

Chemical burns are an important cause of occupational injury.13 Copious irrigation is the primary method of treating all chemical burns; however, certain types of burns require specific antidotes and therapies (Table 211-4).14

Inorganic Acids

Inorganic acids are used in large quantities in industry; some of the occupations at risk for exposure are listed in Table 211-5. Acids are common causes of chemical burns and can cause erythema, blistering and necrosis, and discoloration of the skin. Mechanisms of action of common industrial irritants, including acids, are listed in Table 211-6.

Organic Acids

Organic acids, such as acetic, acrylic, formic, glycolic, benzoic, and salicylic acids, are less irritating than some other acids but can cause chronic irritant dermatitis after prolonged exposure. Formic acid has greater corrosive potential than other organic acids. Fatty acids, such as palmitic, oleic, and stearic acids tend to have low irritant potential.

Hydrofluoric Acid

Hydrofluoric acid (HF) is extremely irritating, even in low concentrations (15%–20%). Fluoride ions penetrate deep into the tissues and bind to calcium and magnesium ions, causing severe tissue damage including bone destruction, especially of the terminal digits of the hand.14 After exposure to lower concentrations of HF, the onset of symptoms may be delayed until release of fluoride ions occurs in deep tissues. Exposure to HF is a medical emergency requiring topical or subcutaneous administration of calcium gluconate after lavage to bind the fluoride ions (see Table 211-4).

Chromic Acid

Chromic acid is highly irritating, causing ulcerations of the skin (“chrome holes”) and perforation of the nasal septum. It can be absorbed and lead to renal failure.15

Alkalis

Alkalis saponify surface lipids and penetrate easily, leading to severe and extensive tissue destruction, including deep ulcerations that heal very slowly (see Table 211-5).

Cement

Exposure to wet cement may cause severe alkaline and thermal burns due to the exothermic reaction of calcium oxide with water to form calcium hydroxide.16 Kneeling in wet cement for prolonged periods leads to deep burns of the knees (“cement knees”) and shins.17 Burns may also result from the trapping of wet cement in gloves and boots.

Other Chemicals and Agents

Phosphorus

Phosphorus can cause deep, destructive burns. It ignites spontaneously on exposure to air. The affected area should be kept moist until the chemical is completely removed. Severe metabolic derangements have been reported after phosphorus burns, and patients should be closely monitored for multiorgan failure.18

Ethylene Oxide

Ethylene oxide burns may result from contact with porous materials and devices that have been sterilized with ethylene oxide but not properly aerated.19 Ethylene oxide may cause delayed irritant reactions (see Table 48-5). Rarely, allergic contact dermatitis is reported to ethylene oxide.66

Phenol

Phenol is rapidly absorbed through intact skin and can cause local necrosis and nerve damage.

Solvents