Contact Dermatitis
Basics
Description
An acute or chronic inflammation of the dermis and epidermis as result of either direct irritation to the skin (irritant contact dermatitis) or delayed-type (type IV) hypersensitivity reaction to a contact allergen (allergic contact dermatitis)
Epidemiology
Incidence
Incidence in children is not known.
Prevalence
- Irritant contact dermatitis: Most cases of contact dermatitis (>80%) are due to irritants.
- Skin reactivity is highest in infants and tends to decrease with age.
- Allergic contact dermatitis
- Because children have less time to develop sensitivities, it is less common in infants and children than in adults.
- Prevalence increases with age.
- Overall prevalence is ~13–23% and has been increasing in children, perhaps due to more frequent exposure to allergens at a younger age or improved diagnosis.
- Contact sensitization may complicate the course in >40% of patients with atopic dermatitis.
Risk Factors
- Irritant contact dermatitis
- Frequent hand washing or water immersion
- Atopic dermatitis: Chronically impaired barrier function increases susceptibility to irritants.
- Genetic factors
- Environmental factors such as cold/hot temperatures or high/low humidity disrupt the skin barrier.
- Allergic contact dermatitis
- Atopic dermatitis
- Skin barrier disruption from injuries or wounds
- Genetic factors
- Increased exposure to allergens
General Prevention
Minimize contact exposure to known or potential irritants and allergens and maintain the barrier function of the skin.
Pathophysiology
- Irritant contact dermatitis does not involve an immune response and thus can occur with the first exposure to the irritant. Multiple mechanisms are involved, including:
- Direct damage to keratinocytes by chemicals (soaps, detergents) or physical irritants (moisture, friction) with resulting disruption of the epidermal barrier and localized release of proinflammatory cytokines
- Chronic exposure may stimulate cell proliferation, resulting in acanthosis and hyperkeratosis with postinflammatory hypo- or hyperpigmentation.
- Allergic contact dermatitis requires initial exposure and sensitization to an allergen and only occurs in susceptible individuals. Repeated exposure leads to the development of a type IV hypersensitivity reaction resulting in proliferation of sensitized T lymphocytes.
- Strong antigens may require only one exposure, whereas weaker antigens may require multiple.
- Exposure can occur transepidermally or systemically.
- Both processes result in nonspecific findings of dermal and epidermal edema and inflammation and may be indistinguishable from other forms of inflammatory dermatitis.
Etiology
- Irritant contact dermatitis
- Frequent hand washing or water immersion
- Soaps and detergents
- Saliva (lip licking or thumb sucking)
- Urine and feces (see “Diaper Rash”)
- High concentrations of most chemicals can induce irritant contact dermatitis, whereas mild irritants may induce inflammation only in susceptible individuals.
- Allergic contact dermatitis
- Nickel and other metals (gold, cobalt)
- Hair products (ammonium, 5-diamine)
- Solvents (toluene-2)
- Cleansers, shampoos (cocamidopropyl betaine)
- Additives to medications, cosmetics (thimerosal, mercuric chloride)
- Rubber
- Fragrances (balsam of Peru [BOP])
- Dyes (cobalt, potassium dichromate, black henna)
- Formaldehydes
- Topical antibiotics (neomycin, bacitracin)
- Topical corticosteroids
- Emollient components (lanolin alcohol)
- Plants (Toxicodendron species; e.g., poison ivy, poison oak, and poison sumac, which contain the allergen urushiol)
Commonly Associated Conditions
Atopic dermatitis or other chronic dermatoses
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Citation
Cabana, Michael D., editor. "Contact Dermatitis." 5-Minute Pediatric Consult, 8th ed., Wolters Kluwer, 2019. Pediatrics Central, peds.unboundmedicine.com/pedscentral/view/5-Minute-Pediatric-Consult/617584/all/Contact_Dermatitis.
Contact Dermatitis. In: Cabana MDM, ed. 5-Minute Pediatric Consult. Wolters Kluwer; 2019. https://peds.unboundmedicine.com/pedscentral/view/5-Minute-Pediatric-Consult/617584/all/Contact_Dermatitis. Accessed November 8, 2024.
Contact Dermatitis. (2019). In Cabana, M. D. (Ed.), 5-Minute Pediatric Consult (8th ed.). Wolters Kluwer. https://peds.unboundmedicine.com/pedscentral/view/5-Minute-Pediatric-Consult/617584/all/Contact_Dermatitis
Contact Dermatitis [Internet]. In: Cabana MDM, editors. 5-Minute Pediatric Consult. Wolters Kluwer; 2019. [cited 2024 November 08]. Available from: https://peds.unboundmedicine.com/pedscentral/view/5-Minute-Pediatric-Consult/617584/all/Contact_Dermatitis.
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