allergens in a fashion similar to adults The distribution, shape, pattern of the rash, and exposure history, may elucidate the cause ( Table 65.3 ) Some common contactants include blue dye in diapers and preservatives in wet wipes, which trigger an itchy diaper rash; toilet seat cleaning supplies triggering “toilet seat dermatitis ” on the posterior thighs; and the vinyl lining of certain car seats which can cause “car seat dermatitis ” on the outer elbows, posterior calves, and occipital scalp Airborne processes (e.g., perfumes, body spray, spray deodorant) can trigger a rash on exposed surfaces, including eyelids, upper chest, distal arms, and legs Photoallergic contact dermatitis occurs when an allergen is applied to the skin and exposed to the sun Common agents implicated include phenothiazines, sulfonamides, thiazides, sunscreen components such as PABA, and some fragrances TABLE 65.3 CAUSES OF CONTACT DERMATITIS Allergen/irritant Distribution Poison ivy, oak, or sumac Linear plaques with vesicles and crusting “Black dot poison ivy” (see above) Lower abdomen (belt buckle, jean snaps); earlobe (earrings); preauricular and hands (cellphones) Around wounds and abrasions Eyelids Exposed surfaces including eyelids, face, upper chest, arms Widespread under clothing Widespread under clothing Groin region in contact with blue dye Nickel and cobalt Neomycin Nail polish (acrylates) Fragrances (airborne) Fragrances (in detergents) Dyes (in clothing) Disperse blue dye (in diapers) Car seat lining (irritant vs allergic) Mango peel Wet wipes (methylisothiazolinone) Cocamidopropyl betaine (soaps and shampoos) Lanolin (found in emollients) Botanicals (found in many organic emollients) Rubber and leather (e.g., shoes) Toilet seats (cleaning supplies) Sunscreens, fragrances (photoallergic contact Occipital scalp, extensor elbows, posterior thighs, posterior lower legs Perioral, hands Perianal, groin, and perioral Widespread Widespread Widespread Dorsal feet sparing, especially great toe May affect soles Posterior thighs May form ring including lateral and superior buttocks Photodistributed (face, chest, dorsal hands, and forearms) dermatitis) Irritant Contact Dermatitis A primary irritant dermatitis is a nonallergic reaction of the skin caused by a single exposure or repeated contact with an irritating substance Strong soaps and detergents, acidic juices, saliva, urine, stool contents, fiberglass particles, and bubble baths are common causes in children Lip licker’s dermatitis occurs as a result of excessive drooling, lip smacking, or lip licking, typically presenting as a sharply demarcated rash around the mouth Juvenile plantar dermatosis is a form of irritant contact dermatitis resulting from exposure to wetness (e.g., sweat) and occlusive footwear without socks This presents with skin fissuring and a glazed appearance of the plantar surface of the foot It may be treated with emollients, topical steroids, and breathable socks Frictional lichenoid dermatitis is likely related to repeated rubbing and presents as shiny papules on the elbows, knees, and back of the hands, and occurs more frequently in individuals with atopic dermatitis This condition is usually noted incidentally and is asymptomatic Treatment of the above conditions includes minimizing contact with the primary irritants, frequent application of petroleum-based barrier ointments, and topical corticosteroids when needed Autoeczematization Autoeczematization, or an Id reaction, occurs in the presence of an allergic contact dermatitis The patient later develops a more extensive monomorphous papular eruption, often accentuated on the extensor aspects of the elbows and knees as a result of autosensitization A specialized form of this process is seen with dermatophyte infection—in particular, tinea capitis—and is called a dermatophytid Dermatophytid reactions can be widespread on the head, neck, and body and are seen most commonly within the first week after initiating oral antifungal therapy for tinea capitis Treatment of Id reactions includes removal or treatment of the inciting agent (allergen or tinea) and topical steroids for itching PHOTOSENSITIVITY Photosensitivity broadly refers to abnormal or adverse skin reactions to sunlight While excessive sun exposure leads to sunburn reactions in most