Few circumstances in dermatology warrant antimicrobial prophylaxis. In cutaneous surgery postoperative infections are too infrequent and insufficiently severe to justify preventive antibiotics, except rarely. Petrolatum is as effective as, and cheaper than, topical antibiotic ointment to cover surgical wounds. In patients with numerous staphylococcal skin infections, oral clindamycin 150 mg every day for 3 months safely reduces further episodes. For recurrent cellulitis, oral penicillin or erythromycin 250 mg twice daily or monthly intramuscular benzathine penicillin decreases subsequent attacks. In patients with frequent episodes of genital or labial herpes simplex an antiviral agent such as valacyclovir 500 mg to 1 g every day is effective as a suppressant.
THE TERM “prophylaxis” has been applied to several different circumstances, depending on whether the organism is exogenous or part of the normal resident flora and whether the antimicrobial agent is given before or after the microbe has reached the target tissues