Table 2.
Topical therapies reported in HS and descriptions of antibacterial, keratolytic and anti-inflammatory effects. The associated quality of evidence supporting the use of topical therapies is reported in the far-right hand side column.
| Topical therapy | Mechanism(s) of action |
Quality of evidence15 | ||
|---|---|---|---|---|
| Antibacterial effect | Keratolytic effect | Anti-inflammatory effect | ||
| Chlorhexidine | Cell wall binding K+ efflux Poor effect on biofilm |
Nil | Nil | C |
| Povidone iodine | Free radical oxidation of DNA/RNA/membrane proteins Some biofilm activity |
Nil | Inhibition of MMP production, TNF-α | C |
| Pyrithione zinc | Bacteriostatic and antifungal: disruption of ATP and protein synthesis. Modulates cellular copper influx. Effect against yeast biofilms |
Nil evidence | Only in the presence of intracellular zinc ions. Can increase TNF-α and HSP-70 in keratinocytes at high concentrations | C |
| Hydrogen peroxide | Free Radical Oxidation of DNA/RNA/Membrane proteins Some biofilm activity |
Possible direct oxidation: nil evidence | Decrease ubiquination in NFκB pathway but higher concentrations display deleterious effects | C |
| Sodium hypochlorite | Free radical oxidation of DNA/RNA/membrane proteins High biofilm activity |
Possible direct oxidation: nil evidence | Decreases NF-κB signaling | C |
| Triclosan | Disruption of bacterial wall synthesis | Nil | Downregulates TLR signaling, IL-6, IL-1ß expression | C |
| Clindamycin | Bacteriostatic effect 50S ribosomal binding | Nil | NF-κB and AP-1 gene expression, regulation of macrophage function., reduction in expression of virulence factors | C |
| Azelaic Acid | Bacteriostatic and antifungal | Nil | Modulation of PPAR-γ function, reduction in IL-6, IL-1ß TNF activity | C |
| Retinoids | Nil | Indirect effect through AP-1 and NF-κB modulation | NF-κB and AP-1 modulation, TLR2, MMP1 and MMP9 downregulation |
C |
| Resorcinol | Membrane damage and K+ efflux | Minor at reported concentrations | Reported but mechanisms not described | C |
AP-1, activator protein 1; ATP, adenosine triphosphate; HS, hidradenitis suppurativa; IL, interleukin; MMP, matrix metalloproteinase; NF-κB, nuclear factor kappa B; PPAR, peroxisome proliferator-activated receptor; TNF, tumor necrosis factor; TLR, Toll-like receptor.