Snapshot A 17-year-old girl presents to her primary care physician with symmetric swollen eyes. On further questioning, she reveals that she recently changed her brand of eye shadow. On exam, only her upper eyelids are erythematous with vesicles. She is instructed to stop the eyeshadow immediately. Given the sensitive nature of eyelids, she is given petroleum jelly to soothe the contact dermatitis. She is reassured that this will resolve. Introduction Clinical definition erythematous and pruritic rash caused by cutaneous exposure to allergens most common form of contact dermatitis to irritants often involves hands often from occupational exposures Epidemiology demographics female > male risk factors exposure to potential allergens or irritants occupations with higher risk of contact dermatitis healthcare food production cosmetics farming Etiology most common allergens include poison ivy poison oak poison sumac nickel most common irritants include chemicals alcohol creams Pathogenesis allergic contact dermatitis immunologic reaction to allergen causing type IV hypersensitivity reaction delayed T-cell mediated reaction activation of Th1 cells memory CD4+ cells are created and dermatitis develops upon re-exposure or cross-reaction irritant contact dermatitis nonimmunologic reaction to substance that causes direct damage to the skin release of inflammatory cytokines activated by non-immune pathways Prognosis typically resolves with treatment Presentation Symptoms presents 12-48 hours after exposure to allergen presents minutes to hours after exposure to irritant pruritic burning or stinging Physical exam linear or geometric rash, corresponding to topical exposure, composed of papules and vesicles can progress to blisters and bullae for example, patients allergic to the adhesive in a bandaid will present with a square or rectangular-shaped rash eczematous rash lichenification fissuring scaling Studies Labs none Patch testing to identify potential allergens to help prevent future exposures Histology spongiosis Differential Atopic dermatitis Treatment Conservative skin moisturizer indication decrease irritation in nonimmunologic contact dermatitis Medical topical corticosteroids indication localized or mild-to-moderate disease first-line therapy topical tacrolimus indication when corticosteroids are contraindicated systemic corticosteroids indications widespread or severe disease disease that involves mucosa Comlications Postinflammatory hypo- or hyperpigmentation Secondary bacterial infection