SATURDAY

October 19

SESSION 4

3:50 – 4:10

Jerry Tan

The current rationale for use of topical antibiotics in acne is predicated on the pivotal role of P. acnes in pathogenesis of inflammation:

1.      P. acnes can induce lymphocyte activation by antigenic and mitogenic mechanisms (Jappe, 2002).

2.      Furthermore, a soluble lipopolysaccharide-like factor of P. acnes can induce proinflammatory cytokine production in monocytic lines (Leyden et al 1995)

3.      Subsequent signal amplification (IL-1 beta, TNF alpha,IL-8, IL-10) results in inflammatory lesions while activation of matrix metalloproteinases can lead to collagen degradation and scarring (Kang, 2002).

4.      Perifollicular activated monocytes (see above #1) have been found to contain steroid sulfatase which can increase local androgenic stimulation of sebaceous glands leading to their hypertrophy and proliferation (Billich et al, 2002)

The widespread use of antibiotics has led increasingly to emergence of resistant strains of P. acnes globally. Patients with such strains have been found to be colonized at multiple sites including the nares. Therapeutic failure of antibiotics in acne has been associated with resistant strains of P. acnes.

One strategy to reduce the emergence of resistant P. acnes is to use benzoyl peroxide, a broad spectrum antibacterial agent acting through reactive oxygen species. Resistance mechanisms to this mechanism of direct bacteriocidal activity are unlikely to develop.

Clinical trials with benzoyl peroxide combined with topical erythromycin and with clindamycin have demonstrated that combination products were significantly superior to individual agents in global improvement acne scores, and reduction in inflammatory lesions. The combination of 1% clindamycin phosphate with 5% benzoyl peroxide demonstrated a 61% reduction in total lesion counts - significantly superior to that for benzoyl peroxide alone ((39%) and clindamycin alone (35%). (Lookingbill et al, 1997).

The addition of benzoyl peroxide is a rational and effective strategy when used in combination with topical or oral antibiotics to enhance therapeutic outcome in individual acne patients and to reduce the risk of selection of resistant cutaneous bacteria.