A 43-year old man comes to the physician with a 2-day history of blistering and severe itching on his hand. He developed a superficial burn on his index finger from hot candle wax 1 week ago and has been treating the burn with a topical ointment containing neomycin, polymyxin B, and bacitracin. His past medical history is significant for irritable bowel syndrome with chronic diarrhea. The patient is not taking any prescription medications and has no known drug allergies. On examination, he has faint erythema of the skin between the index and middle fingers, several vesicles and small bullae are present as shown in the image below: Which of the following is the most appropriate next step in management of this patient's skin disorder?

Question

A 43-year old man comes to the physician with a 2-day history of blistering and severe itching on his hand.  He developed a superficial burn on his index finger from hot candle wax 1 week ago and has been treating the burn with a topical ointment containing neomycin, polymyxin B, and bacitracin.  His past medical history is significant for irritable bowel syndrome with chronic diarrhea.  The patient is not taking any prescription medications and has no known drug allergies.  On examination, he has faint erythema of the skin between the index and middle fingers, several vesicles and small bullae are present as shown in the image below:  Which of the following is the most appropriate next step in management of this patient's skin disorder?

Quizplus · Accepted Answer

Explanation: This patient has vesiculation and faint erythema associated with topical antibiotic use; these are typical features of acute allergic contact dermatitis (ACD). ACD is most commonly due to urushiol (ie, poison oak/poison ivy dermatitis). Other common causative allergens include topical antibiotics, fragrances, and a variety of chemicals used in rubber, plastic, and leather processing. Management includes avoidance of the offending agent. Low-potency topical glucocorticoids may also be considered if the itching and discomfort are intolerable. Topical antibiotics are useful for full-thickness burns and partial-thickness burns with loss of epithelium. However, superficial burns with an intact epithelium and most minor cuts and scrapes do not require topical antibiotics as these would only increase ACD risk and contribute to antibiotic resistance. (Choice B) Cephalexin is indicated for moderate skin and skin-structure infections such as cellulitis. However, this patient's skin findings and recent topical antibiotic use are more consistent with ACD. cellulitis (Choice C) Valacyclovir is indicated for the treatment of shingles (herpes zoster). Shingles is characterized by a papular or vesicular outbreak in a dermatomal distribution. Itching is possible, but burning or pain is more typical. shingles (Choice D) Dermatitis herpetiformis (DH) is an autoimmune disorder characterized by pruritic vesicles and papules in a widespread distribution, primarily on the elbows, knees, lower back, and buttocks. It is associated with celiac disease. Skin biopsy is usually performed to differentiate DH from other autoimmune vesicular/bullous diseases. Dermatitis herpetiformis vesicular/bullous diseases (Choice E) Tinea manuum is a superficial fungal infection of the hands that is often seen in patients with pre-existing tinea pedis. Characteristic findings include erythema, cracking, scaling, and pruritus. Tinea manuum Educational objective: Allergic contact dermatitis is a common adverse effect of topical antibiotic use. Topical antibiotics also increase the risk for antibiotic-resistant organisms. References: Postoperative topical antimicrobial use. (http://www.ncbi.nlm.nih.gov/pubmed/18674453) Contact allergy to neomycin sulfate: results of a multifactorial analysis. (http://www.ncbi.nlm.nih.gov/pubmed/15880442)

A 43-Year Old Man Comes to the Physician with a 2-Day