Bullous eruption on the posterior thigh

Empiric treatment of impetigo: Consider a culture for MRSA

For localized impetigo, topical therapy with mupirocin 2% ointment 3 times a day for 10 days is usually adequate. A 10-day course of oral antibiotic therapy with dicloxacillin or cephalexin is indicated in more widespread impetigo presumed to be methicillin-sensitive S aureus. Azithromycin (Zithromax) or clarithromycin (Biaxin) may be given to patients allergic to penicillin.

However, it is becoming increasingly important to consider community-acquired methicillin-resistant S aureus species in cases such as this that do not respond to traditional therapy. Hence, culture and sensitivity of all suspicious lesions is highly suggested.

Patient’s treatment and recovery

In this case, the patient was diagnosed with bullous impetigo and admitted to the hospital. She was started on intravenous clindamycin at 380 mg (30 mg/kg) every 8 hours. Clindamycin was chosen because most cases of community-acquired MRSA in this geographic area are resistant to trimethoprim-sulfamethoxazole and susceptible to clindamycin.

Although doxycycline would have covered both community-acquired MRSA and Lyme disease, we were less suspicious of Lyme given the physical exam of the patient, and we were reluctant to start this patient on doxycycline due to the fact she did not have complete maturation of her dentition.

Within 24 hours of intravenous clindamycin, the lesion was markedly improved and the culture confirmed that the MRSA was sensitive to clindamycin. She was discharged on oral clindamycin at 375 mg 3 times daily, to complete a 14-day course of therapy. The lesion was completely resolved without recurrence within 2 weeks.

CORRESPONDING AUTHOR
Richard P. Usatine, MD, University of Texas Health Science Center at San Antonio, Department of Family and Community Medicine, MC 7794, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900. E-mail: usatine@uthscsa.edu