DDx
Diagnostic Considerations
Other problems to be considered in patients with possible contact dermatitis include the following:
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Insect bites
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Bed bug infestation
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Erysipelas
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Erythema multiforme
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Nummular eczema
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Lichen simplex chronicus
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Xerosis
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Asteatotic eczema
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Bullous disorders (eg, bullous pemphigoid, pemphigus, epidermolysis bullosa)
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Tinea
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Jellyfish envenomation
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Lupus erythematosus in infants and children
Differential Diagnoses
Media Gallery
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Dry, fissured, pruritic eczema is frequently the result of excessive washing and very low humidity in cold climates. Irritant contact dermatitis is due to direct injury of the skin. In this patient, frequent handwashing and use of soap is the cause of damage to the protective layers of the upper epidermis. Patients should be educated about the cause of the dermatitis and instructed in methods of skin protection and care with emollients.
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Nickel is the most frequent contact allergen in females older than 8 years, and allergy occurs in as many as 25% of females 14 years or older. Allergens, such as nickel, are impossible to completely avoid. Exposure can be reduced with careful instruction, but occult exposures may produce chronic or recurrent symptoms. Nickel in the watch and watch band produced this episode of allergic contact dermatitis.
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Allergic reactions to rubber products are usually caused by antioxidants and accelerators added in the manufacturing process, rather than the rubber itself. Antioxidants help preserve the rubber, and accelerators help in the vulcanization process. Exposure to rubber in gloves, shoes, undergarments, tires, heavy-duty rubber goods, and sport goggles is common.
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The typical eruption from poison ivy includes erythema, edema, papules, vesicles, and bullae. Linear streaks as in this patient are characteristic but are not always present. Initial yellow crusts are dried serum from ruptured bullous lesions and not evidence of infection. Oleoresin (urushiol), which exudes from damaged areas of poison ivy, poison oak, and poison sumac, turns black after exposure to air. Fresh oleoresin on the skin dries and may be observed as black smudges or spots.
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When limes are squeezed into beverages, excess juice remains on the skin. Many other foods can cause similar reactions, i.e. the phytophotodermatitis. Sun exposure of this lime juice produces areas of dermatitis or hyperpigmentation. Perfumes are also common sources of photo contact dermatitis.
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Most common moisturizers contain various additives and preservatives. The list of ingredients on this bottle is not uncommon, and most of these agents are capable of causing allergic contact dermatitis. Patch testing with dilute concentrations of the individual ingredients can be used to identify the agent that is a problem for any particular patient.
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Areas of acute contact dermatitis respond well to cool compresses and wound care. Moist compresses are soothing, have a mild antipruritic effect, reduce serous drainage, and gently debride the wound. Clean water, isotonic sodium chloride solution, and Burow solution all can be used. Compresses should be kept moist at all times. Wet-to-dry compresses are painful and destroy fragile tissues. Following moist compress applications for 5-10 minutes, affected sites should be gently cleared of loose crusts and a thin coat of Vaseline or antibacterial ointment should be applied.
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Urticaria, also known as hives or whelps, involves edematous pale or pink plaques. Agents can produce urticaria by immunologic reactions, by nonimmunologic reactions, or by unknown mechanisms. Nonimmunologic reactions are most common. Other types of environmentally associated urticaria must be excluded. This is an example of cold urticaria produced by application of an ice cube to the dorsum of the arm.
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Prolonged use of moderate- to high-potency topical steroids may cause skin atrophy or steroid acne. This patient used a moderate-strength steroid, triamcinolone 0.1%, in this area for several weeks. Steroid acne, also called steroid rosacea, has a classic appearance with monomorphic erythematous papules. If the steroid is discontinued, the condition usually worsens. Patients must understand that symptoms worsen before they improve, and several weeks or months are required to taper off this steroid.
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This purpuric reaction was noted after application of eutectic mixture of local anesthetics (EMLA) for 1 hour. EMLA cream is widely used as a local anesthetic for superficial procedures. Blanching and redness are commonly observed side effects. Dramatic purpuric reactions to EMLA, as in this patient, have been reported. Patch test results in these patients with the individual ingredients of EMLA cream, EMLA cream itself, placebo cream, and Tegaderm are negative. Apparently, the purpuric reaction is not of an allergic nature, but the cream may have a toxic effect on the capillary endothelium.
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