A 13-year-old boy is brought to the office for an itchy rash he developed yesterday during a camping trip with his father. The rash started on his legs and spread to his arm this morning. His father developed a similar rash on his legs and face. They came to the office immediately after returning early from the trip due to the boy's pain and intense itching. The patient's father applied topical diphenhydramine, which did not provide relief. He has no other medical issues and takes no other medications. Other than a family trip to Europe last month, the patient has not traveled out of the United States. Physical examination shows an uncomfortable-appearing boy. Scattered areas of erythematous papules are present on the right arm, with several overlying vesicles filled with clear fluid. Many linear erythematous lesions are also found on the anterior lower extremities, some of which have vesicles oozing a serous fluid. Which of the following is the best recommendation for reducing the spread of this patient's condition?
Show Explanatory Sources
Poison ivy contact dermatitis is a type IV (cell-mediated) hypersensitivity reaction that classically presents with linear papules and clear, fluid-filled vesicles on exposed areas. Pain and intense pruritus are typical. Nonlinear lesions can also be present from subsequent spread via contact with residual plant resin on contaminated clothing. Immediate removal of contaminated apparel and gentle cleansing of exposed areas are recommended to minimize spread of dermatitis.
Treatment is supportive (eg, cool compress, topical corticosteroids). Oral corticosteroids are indicated in severe dermatitis or dermatitis involving the face or genitalia to reduce inflammation. Antihistamines (eg, diphenhydramine) are not effective as the pruritus in poison ivy dermatitis is not histamine-mediated (Choice C).
(Choice A) Topical antibiotic therapy is indicated for bacterial superinfection of poison ivy contact dermatitis. Presentation includes honey-crusted lesions or an exudative discharge. This patient's vesicles are filled with clear fluid and oozing serous fluid.
(Choice B) Oral ivermectin is the treatment for scabies, which also presents with an intensely pruritic rash. Distribution of the rash, however, classically involves the web spaces of the hands and feet, axillary folds, and genitalia.
(Choice E) Insecticides are indicated in the management of bedbug infestation. Presentation includes small (2-3 mm) erythematous papules, often in a linear pattern, on exposed areas. Pruritus is common, but pain and vesicular lesions are atypical. In addition, this patient's recent camping history makes poison ivy contact dermatitis more likely.
Educational objective:
Poison ivy contact dermatitis presents as pruritic, linear papules and/or vesicles on exposed areas. Reduction of spread is achieved by avoiding both direct (eg, skin-to-plant contact) and indirect (eg, clothing) exposure to the allergen.