Chlorhexidine Use on Open Grazes
Chlorhexidine should NOT be routinely used on open grazes or wounds that extend beyond the superficial layers of skin, as it can delay wound healing and cause tissue damage. 1
FDA Contraindications and Warnings
The FDA explicitly states that chlorhexidine "wounds which involve more than the superficial layers of the skin should not be routinely treated" with this agent. 1 This is a clear contraindication that takes precedence over other considerations.
Mechanism of Harm in Open Wounds
- Chlorhexidine is highly cytotoxic to fibroblasts, the cells essential for wound healing, even at concentrations as low as 0.002%. 2
- Cell proliferation is almost completely suppressed by chlorhexidine exposure, preventing the normal cellular division needed for tissue repair. 2
- Collagen gel contraction is severely impaired, which directly affects wound contraction and closure. 2
- Protein synthesis is suppressed in exposed tissues, further compromising healing capacity. 2
Clinical Evidence of Delayed Healing
Research demonstrates that increasing concentrations of chlorhexidine cause progressively worse delays in wound healing, particularly in wounds where bone or deeper tissues are exposed. 3 In animal studies, wounds treated with 0.5% chlorhexidine showed the worst healing outcomes compared to control groups. 3
Appropriate Use of Chlorhexidine
Chlorhexidine is indicated for:
- Intact skin antisepsis before procedures such as catheter insertion or surgery. 4
- Superficial skin cleaning after minor injury that does not breach deeper skin layers. 5
- Preoperative skin preparation on intact skin (avoiding head, face, and genital areas). 1
The agent should be 2% chlorhexidine gluconate in 70% isopropyl alcohol for optimal antimicrobial efficacy on intact skin. 4
Recommended Alternative for Open Grazes
For open grazes and superficial wounds:
- Clean with normal saline or clean water to remove debris
- Povidone-iodine 2% is preferred over chlorhexidine for wounds requiring antisepsis. 6, 7
- Allow the wound to heal by secondary intention with appropriate dressing changes
- Avoid repeated antiseptic applications to open wounds as this impairs healing. 3
Critical Safety Considerations
- Allergic reactions ranging from contact dermatitis to anaphylaxis can occur, though uncommon. 6, 8, 9
- Never use in infants under 2 months of age due to risk of systemic absorption and chemical burns. 4, 6
- Avoid contact with eyes, ears, and mucous membranes as chlorhexidine can cause permanent damage. 6, 10, 1
- Stop use immediately if irritation or sensitization occurs and persists beyond 72 hours. 1
Common Pitfall to Avoid
Do not assume that because chlorhexidine is an excellent antiseptic for intact skin, it is appropriate for all types of wounds. The cytotoxic effects that make it antimicrobial also make it harmful to healing tissues in open wounds. 2