Chapter 9: Preoperative and Postoperative Antibiotics

INTRODUCTION

A discussion of antibiotic use in procedural dermatology should begin with the principles of when not to use antibiotic agents, as the majority of cutaneous procedures do not require their use. The dermatologic surgeon, like any medical practitioner, should be guided by the fundamental rule primum non nocere—first do no harm. Medications, including topical antibiotics, have side effects. They also have costs, both to the patient and to health care systems, whether direct financial ones or indirect ones, such as from the emergence of multidrug-resistant microorganisms.

Evidence-based medicine teaches us that the use of routine antimicrobial prophylaxis, which was once common practice in dermatologic surgery, is no longer indicated. This principle applies both to topical and systemic antibiotic agents. The incidence of wound infection in cutaneous surgery is very low. Rates of surgical site infection in clean wounds typically range between 1% and 3%.^1–4 In Mohs surgery, rates fall below 3% (Table 9-1).

The risk of iatrogenic bacteremia following dermatologic surgery on clean skin has been found to be smaller than the risk of random bacteremia in healthy individuals leading a normal lifestyle.⁴ For example, the risk of bacteremia following teeth brushing has been estimated to be between 20% and 40%, compared to <2% for surgery on clean, nonmucous membrane skin.⁶

Certain anatomic sites, such as the lips, ears, and groin, are susceptible to a higher risk of bacteremia.⁷ Similarly, any breach in mucous membranes leads to higher risk of surgical site infection.⁸ Thus, procedures on certain anatomic sites may warrant prophylactic antibiotic coverage (Fig. 9-1). Postoperatively, all wound infections require antibiotic treatment, and those that are frankly purulent or fluctuant require drainage and occasionally packing as well. This assumes, however, that one can distinguish natural wound healing from wound infections. For example, nonpurulent erythema may be the result of irritation from sutures rather than bacterial colonization. In such cases, simple removal of the sutures will alleviate the patient’s symptoms and promote healing. Clinical signs which help to differentiate between these possibilities include minimal warmth, tenderness, and induration, absence of fever, and inability to express purulent material for wounds reacting to suture as opposed to infection (Fig. 9-2). Clinical experience with the normal healing process is particularly important during postoperative days 3 to 10 when low-grade cellulitis may be more difficult to distinguish from a suture reaction. Sutures have varying tissue reactivity, and familiarity with suture properties is important when assessing postsurgical wounds. Specific procedures, such as skin grafts and larger flaps, have higher associated infection risks and so may favor the use of prophylactic antibiotics.^7...