Topical antimicrobial therapy
Topical antimicrobial therapy includes topical antibiotics, antifungals or antiseptics. Antiseptics are disinfectants used to kill or inhibit the growth of micro-organisms, and can be nonselective and cytotoxic. Topical antibiotics also kill or inhibit the growth of bacteria, but generally have a narrower spectrum of activity and are more likely to cause bacterial resistance. Topical antifungals disrupt proliferation of fungus.
Topical antimicrobial therapies include:
- silver dressings (foam, alginate, gelling fibre, nanocrystalline, carboxymethylcellulose)
- iodine solution and dressings (povidone-iodine, cadexomer iodine)
- sterile medical grade honey (gel, dressing)1
- alginogels (ie Flaminal range)
- bacteria-binding dressings (eg Sorbact range)
- antiseptic or surfactant solutions for cleansing, and gels for dressings.
Use antiseptics (eg chlorhexidine, povidone-iodine, polyhexamethylene biguanide [PHMB], octenidine dihydrochloride) for local infection (either covert or overt; see c_lwg2-c18-s2-1.html#lwg2-c18-s2-1__tlwg2-c18-tbl2) or dirty wounds. See Cleansing and debridement for more information.
Topical antibiotics (eg creams or ointments) are not recommended because they can be sensitising agents, have no demonstrated effect on healing, and promote antimicrobial resistance. An exception is topical metronidazole gel for the management of malodorous wounds. Topical antibiotics intended for intact skin, or use in eyes or ears (eg chloramphenicol) are inappropriate for use on the exposed tissue of a wound.
If an antimicrobial dressing is used, choice should be based on the amount of exudate, patient allergies or sensitivities, affordability, access and evidence of efficacy. Currently, limited evidence exists to suggest one antimicrobial dressing has greater clinical efficacy than another. Current evidence suggests that cadexomer iodine may speed healing of infected venous leg ulcers compared with standard care; honey may speed healing of infected surgical wounds compared with an antiseptic and gauze.
Antimicrobial dressings should be used for the shortest time possible, and in addition to standard ulcer care and interventions (eg cleansing and debridement, pressure offloading). Review the patient 2 weeks after starting a dressing regimen. If signs of infection have resolved, change to a nonantimicrobial dressing based on the wound characteristics (see Ulcer and wound dressings). If signs of infection remain, ensure adequate cleansing and debridement. Consider either continuing with the current dressing regimen for another 2 weeks, or referring for further investigations and treatment, especially if infection is worsening. Usually, silver-based dressings are used for 2 weeks (per manufacturer's instructions).
Theoretical concerns exist about systemic iodine absorption from iodine-based dressings. Use these dressings with caution in children younger than 6 months, for durations longer than 1 week, or for extensive open wounds.