Question

A 10 year old boy returns to the physician for a non-healing rash on his arms, legs, and face. Two weeks ago, he initially developed a small, intensely pruritic area of erythema on his arm that progressed into small fluid-filled blisters. He was initially treated with prednisone for contact dermatitis, but after the rash continued to spread, he was given a prescription for cephalexin. Despite finishing the course of cephalexin, the rash has continued to spread to his legs, neck, and face. The patient's immunizations are up-to-date, and he has never been hospitalized and takes no chronic medications. On physical examination, the child is comfortable and pleasant, with vital signs including temperature 36.8 C (98.2 F), pulse of 90/min, blood pressure 100/68, and oxygen saturation of 99% on room air. There are numerous linear areas of erythema and excoriation are noted on the patient's arms, legs, neck, and face. The lesions appear to be in various stages of evolution: some are vesicular, while some are covered with a golden-yellow crust. Gram stain of one of the lesions shows numerous Gram-positive cocci in clumps. Which of the following is the most appropriate treatment for this patient at this time?

A. Trimethoprim-sulfamethoxazole
B. Acyclovir
C. Dicloxacillin
D. Vancomycin
E. Varicella zoster immune globulin (ZVIG)

Answer 1

To treat the rash presented by the 10-year-old patient, which is indicative of impetigo, the most appropriate antibiotic is dicloxacillin. This antibiotic is suitable for treating staphylococcal infections, which the Gram stain suggests to be the cause of the impetigo.

Step-by-step explanation:

The patient's presentation of a non-healing rash with a progression from small, intensely itchy and erythematous areas to fluid-filled blisters, and finally to lesions in various stages covered with a golden-yellow crust, alongside the Gram stain showing Gram-positive cocci in clumps, strongly suggests a diagnosis of impetigo. Given the bacterial findings from the gram stain, the most appropriate treatment would be an antibiotic effective against staphylococci. From the options provided, dicloxacillin is commonly used for treating impetigo caused by staphylococcal infections. Dicloxacillin is preferred over the use of vancomycin, which is generally reserved for methicillin-resistant Staphylococcus aureus (MRSA) infections or patients who cannot tolerate penicillin-type antibiotics. Trimethoprim-sulfamethoxazole is also used for MRSA infections. Acyclovir would be indicated for viral infections such as herpes or varicella-zoster, which do not align with the presented symptoms or Gram stain results. Varicella zoster immune globulin (VZIG) is not appropriate, as the child's presentation does not fit with a primary varicella infection, and his immunizations are up-to-date.