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Although human skin can withstand many of the assaults of a hostile environment; skin is the most commonly injured organ in industry. Skin disorders comprise more than 35% of all occupationally related diseases, affecting annually approximately one worker per thousand. Reporting remains highly incomplete, however, and the hardship and financial loss to workers and employers alike are substantial. Most occupational skin disease results from contact with a chemical substance, of which there are more than 90,000 in the environment today. Under certain conditions, all of them can irritate the skin, and approximately 2000 substances are now recognized as contact allergens. In addition, workers bring to their work preexisting diseases, which can be aggravated by their work.
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Contact dermatitis (CD) of the hands is the most common occupational skin disease and atopy is often an important cofactor. CD can be subdivided into irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD) (Figure 21–1).
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Irritant Contact Dermatitis
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Essentials of Diagnosis
Acute and subacute effects
Single exposure to a strong irritant is sufficient
Usually hands involved
Raw appearance and erythema of the affected body part
Demarcated areas from the normal skin
Cracking\chapping of the affected body part
Fissuring
Bleeding
Pustular skin changes
Itching\burning with or without visible skin changes
Chronic effects
Repeated exposures required
Skin dryness
Hyperkeratosis
Skin itching (less than in ACD)
Skin wrinkling
Development of allergic contact dermatitis
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General Considerations
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ICD is a spectrum of disease processes with a complex pathophysiology, a varied natural history, and divergent clinical appearance. This contrasts with ACD, in which a specific chemical is the central cause. Many factors can induce irritant reactions, either in isolation or in combination. These include the intrinsic nature of the substance (ie, pH, solubility, physical state, and concentration), environmental factors (ie, temperature, humidity, and pressure), predisposing individual characteristics (ie, age, gender, ethnicity, concurrent and preexisting skin disease, and the skin region exposed), and genetic factors such as filaggrin (FLG) gene mutation. Irritant contact dermatitis is a common form of occupational skin disease and, in the United States, accounts for nearly 80% of all occupational dermatitis.
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There are at least 14 biologic entities within the irritant dermatitis syndrome.
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Acute irritation/corrosion refers to a single exposure of a material that is so irritant that damage is seen within hours to a day or so. Typically, this is caused by exposure to strong acids and bases (Table 21–1). Many other chemicals produce similar exaggerated effects. The likelihood of a mixture producing such acute irritation frequently can be estimated by high concentrations of chemicals with extremes of pH.
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