Application of topical treatments like topical retinoids, topical antibiotics, or a combination of both, is recommended to patients suffering from mild to moderate comedonal or papulopustular forms of acne, depending on the severity and the nature of acne lesions. These agents influence the pathogenic factors responsible for acne formation directly or indirectly.

Topical Antibiotics

The efficacy of topical antibiotics has presently waned due to increasing bacterial resistance. Today’s dermatologists suggest that topical antibiotics should be used in combination of topical retinoids or benzoyl peroxide or azelaic acid for greater effects, as well as prevail over bacterial resistance.

When used with other antimicrobial agents, topical antibiotics are best for treating mild inflammatory acne with the presence of few papules, pustules, and few comedones. Application of this combination twice a day produces good results.

Two of the most commonly used topical antibiotics are clindamycin and erythromycin. Some other antibiotics are used topically but are not popular due to their low efficiency and higher rates on adverse side effects formation.

The Function of Topical Antibiotics

Erythromycin and clindamycin, like any other topical antibiotics, work by reducing the population of P. acne in the epidermal surface on the hair follicles. This then lessens the lipids on the skin surface, which are produced by the lipase activity of P. acne. Inflammatory cell chemotaxis is curbed by the mild anti-inflammatory effect of topical antibiotics and Clindamycin in particular has the ability to reduce the formation of comedones indirectly. Topical antibiotics do not cause extreme levels of skin irritation compared to some topical retinoids. So, topical antibiotics operate by inhibiting the inflammation caused by the bacteria rather than attack the acne directly.

The Disadvantages Associated with Topical Antibiotics

The only problem (and probably the most major) with topical antibiotic which has been proven over the past two decades is that extensive use results in increasing bacterial resistance. Thus, topical antibiotics should never be used alone over a long period. If antibiotics must be administered on its own, the regimen must be completed within a short period of time (around 3-4 weeks), because once P. acne became resistant to antibiotics, the affected individual’s health may be jeopardized. It is therefore recommended that anti-microbials be used with antibiotics in treatment to suppress the existing P. acne resistant strains as well as cancel the formation of new varieties. The combination also stops the colonization of antibiotic-resistant Staphycoccus aureus. Adverse effects of using topical antibiotics as monotherapy include peeling, dryness, burning, relatively low onset of action, and erythma. Once inflammatory lesions are reduced, treatments should be immediately stopped.

Clindamycin

Clindamycin is a synthetic antibiotic that has a long history of success in treating acne vulgaris because it is mostly safe and well tolerated. It reduces the number of P. acne since it controls the inflammation and thus the severity of acne. Topical Clindamycin is available as a solution, ointment, gel, or pledgets, as well as liquid form in combination with zinc acetate, reducing P. acne counts and decreases free fatty acids and surface lipids. Two topical Clindamycin products are available in the market – Dalacin T and Zindalcin.

Erythromycin

Erythromycin’s effectivity in treating mild to moderate P. acne has also been established. It reduces the P. acne counts and decreases the Micrococcaceae from the ducts of the sebaceous glands. Although there have been newer varieties of P. acne that are more resistant to erythromycin, these were countered by using 4% erythromycin formulation. It has also been found that adding zinc acetate in the erythromycin formulation enhances the suppression of sebum as well as the treating capability against bactericidal effect of erythromycin.

Topical Antibiotics Combined with Other Anti-bacterials

Fixed combinations of topical antibiotic with benzoyl peroxide, retinoid, and zinc are used in order to maximize the bactericidal effect as well as quell the effects of bacterial resistance. Factors that are involved in the overall effect of topical antibiotics on acne lesion are brought about by better absorption of the drug and improved patient cooperation. The standard available fixed combinations include erythromycin 3% with benzoyl peroxide 5%, erythromycin 4% with tretinoin 0.02% gel, erythromycin 2% with isotretinoin 0.5% gel, erythromycin 1.2% with zinc acetate 0.377% solution, clindamycin 1% and benzoyl peroxide 0.5% gel, and clindamycin 1% with tretinoin .02% gel.

85% of the inflammatory lesions can be reduced by a combination of 4% erythromycin and zinc compared to a 46% reduction using 2% erythromycin alone. In three clinical studies that involves 1259 patients, the result shows that a combination of 1% clindamycin with 5% benzoyl peroxide is more effective than either using drug that reduces lesions or drugs that suppresses P. acnes. Over a period of 12 weeks, it was found out that 1% Adapalene gel plus 1% clindamycin reduces significantly the inflammatory as well as non-inflammatory lesions.