Irritant Contact Dermatitis at a Glance
- Irritant contact dermatitis (ICD) is a nonimmunologic inflammation of the skin caused by contact with a chemical, physical, or biologic agent.
- Up to 80% percent of contact dermatitis is irritant and is commonly related to occupation.
- The most important exogenous factor for ICD is the inherent toxicity of the chemical for human skin.
- Endogenous factors, such as skin barrier function and preexisting dermatitis, play an important role in the pathogenesis of ICD.
- Atopic dermatitis is a major risk factor for irritant hand dermatitis because of impaired barrier function and a lower threshold for skin irritation.
- Patch testing should be performed in cases with suspected chronic irritant dermatitis to exclude an allergic contact dermatitis.
- Identification and avoidance of the potential irritant is the mainstay of treatment.
Dermatitis or eczema is a pattern of cutaneous inflammation that presents with erythema, vesiculation, and pruritus in its acute phase. Its chronic phase is characterized by dryness, scaling, and fissuring. Irritant contact dermatitis (ICD) is a cutaneous response to contact with an external chemical, physical, or biologic agent; endogenous factors such as skin barrier function and preexisting dermatitis also play a role (Figs. 48-1 and 48-2). The spectrum of presentation after contact with an irritant varies from overt dermatitis to subjective symptoms, contact urticaria, caustic and necrotic reactions as well as pigmentary changes and other dermatoses.
Irritant contact dermatitis in a welder.
Irritant pustular dermatitis from nickel salts.
In contrast to allergic contact dermatitis (ACD), no previous exposure to the causative agent is necessary in eliciting irritant reactions.1 ICD accounts for 80% of all cases of contact dermatitis,2,3 and is often occupation-related (occupational ICD is discussed in detail in Chapter 211). ICD caused by personal care products and cosmetics is also common; however, very few patients with these irritant reactions seek medical help because they manage by avoiding the offending agent.4
The incidence of ICD is difficult to determine because the accuracy of the epidemiologic data is limited. European cross-sectional studies for eczema due to all causes in the general population have shown point prevalence rates of 0.7%–40% and 1-year to lifetime prevalence rates of 7.2%–11.8%.5 Data from the U.S. Bureau of Labor Statistics show that of the 257,800 cases of nonfatal occupational illnesses reported in 2008 for all industries including state and local government and private industry, 18.9% (48,600 cases) were skin diseases, the second most frequent cause of all occupational illnesses reported.6 Based also on annual surveys of the Bureau of Labor Statistics incidence rates of occupational diseases in the American working population, contact dermatitis constitutes 90%–95% of all occupational skin diseases, and ICD constitutes about 80% of occupational contact dermatitis.7