The prevalence of MRSA is linked to the availability of over the counter topical antibiotics, especially neomycin and bacitracin.1 This begs the question about what the true medical indications are for topical antibiotic use in General Practice.
Oral antibiotics, but not topical antibiotics are indicated for wound infections, cellulitis or other deeper skin infections. It is important to reconsider the use of topical antibiotics in skin infections and reduce inappropriate prescribing.2
Chloromycetin is the only broad spectrum topical antibiotic available for ophthalmic use. Its easy availability over the counter, without prior medical advice, should be of great concern. It is quite bizarre that this should be the case, given that other topical antibiotics require a prescription.
Topical clindamycin and erythromycin are commonly used in the management of acne. Guidelines3 advise the use of topical antibiotics only in combination with other acne treatments, due to the increasing incidence of resistance against both clindamycin and erythromycin.3 Propionibacterium acnes showed no resistance prior to 1975 to these antibiotics, but currently resistance has become noticeable by as little as eight weeks’ topical treatment.3 The use of topical metronidazole for acne rosacea does not appear to have as great a risk of resistance.
Topical antibiotics are generally not indicated in the treatment of infected eczema.2 In the management of impetigo (Staphlococcal or Streptococcal), for topical antibiotics to be effective there should be three or fewer lesions and the total area treated should be under 5cm2. The golden scales should be removed and the affected skin bathed in warm water prior to treatment.2 Despite this, the GP and the patient should be aware of the need to reassess the situation in case oral antibiotics are needed.
The use of topical antibiotics to reduce nasal carriage in patients who have recurrent Staphylococcal boils and infections is controversial. This is because of the possibility of increasing resistance and because the evidence for efficacy in reducing recurrent infections by decolonisation is not clear.2 If it is used, the patient must be compliant and the first line treatment (assuming sensitivity is present) is fusidic acid, followed by mupirocin.2 It is also necessary to combine this with antiseptic washes.
Take home messages
1. Mitka, M. Antibiotic Creams May Be Linked to Increasing Drug Resistance in MRSA Strain. JAMA Forum, Sept. 14, 2011
2. Topical antibiotics: very few indications for use. Best Practice Journal, October 2014
3. Humphrey, S. Antibiotic Resistance in Acne Therapy. Medscape Family Medicine. Skin Therapy Letter. 2012; 17(9)