Contact dermatitis or contact eczema (commonly known) is caused by exposure to substances in the environment. Contact dermatitis occurs in both irritant and allergic forms. Irritant contact dermatitis is a nonallergic reaction occurring in any person on contact with a sufficient concentration of an irritant. It occurs four times more commonly than allergic contact dermatitis. Mechanical irritation may result from wool or glass fibers. Chemical irritants include acids, alkalis, solvents, detergents, and oils commonly found in cleaning compounds, insecticides and industrial compounds. Biologic irritants include urine, feces, and toxins from insects or aquatic plants. Persons engaged in wet work such as food handlers, health care workers, and child care providers are more prone to irritant contact dermatitis.
Allergic contact dermatitis is a cell-mediated type IV delayed hypersensitivity immune reaction from contact with a specific antigen. Many compounds can cause sensitization under specific condition. Typical antigens include poison ivy, synthetics, industrial chemicals, drugs (e.g., sulfanilamide or penicillin), and metals (especially nickel and chromate). Once the skin has been sensitized, further contact with the sensitizing substance will produce an eczematous reaction. The sensitizing allergen may reach the site by direct contact; by direct contact such as transmission from animals, from one part of the body to the other by the hands, or from clothing; or by the air, as in smoke. Investigation of possible exposures, including medications, products (e.g., household cleaning, cosmetics, hobbies), occupational environment, and recreational activities, may provide insight into the contact event.
Pathophysiology
The characteristic lesions of contact dermatitis appear sooner in an irritant contact than in the allergic type; however, the onset and appearance vary, depending on the type and concentration of the irritant. The rash develops on the exposed areas, particularly the more sensitive areas, such as the dorsal rather than the palmar surface of the hands. When contact dermatitis is suspected but the agent is unknown, patch testing may be carried out. And the environment manipulated to exclude suspected agents.
Collaborative Care Management
Weeping vesicular lesions are treated with Domeboro soaks one or two times a day. Crusts and scales are not removed but are allowed to drop off naturally as the skin heals. Topical corticosteroids (middle to potent range) are applied twice a day to affected areas for approximately 2 weeks. Face, genitals, and skin fold sites warrant weaker steroid formulations such as hydrocortisone 0.5% to 1%. Oral corticosteroids may be prescribed for generalized rash or significant hand and face involvement. Oran antibiotics are used only when secondary infection ensues. Oral antihistamines, topical antipruritic agents, or colloidal oatmeal baths and lotions may ease itching.
Patient/Family Teaching
The primary focus of patient teaching is prevention. Contact dermatitis can be prevented by avoiding the irritating or sensitizing substance whenever possible. Patients and family members should be educated to recognize the leaves of Rhus plants – poison ivy, oak and sumac. Persons walking in the areas where these plants grow need to protect the skin by wearing appropriate clothing. If contact with the plant is suspected, symptoms may be averted by immediately rinsing the skin for 15 minutes with running water to remove the resin before skin penetration occurs, and carefully removing clothing to avoid skin contact.
The person who develops sensitivity to material encountered in the living or working environment may need to consider a permanent change of environment if other measures are unsuccessful. Gloves may be used if the person is handling irritant or allergenic substances. Persons sensitive to detergents may need to wash their clothes and bathe with a mild soap product.
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