Wound Dressings in Dermatology

Source: Dermatology 2-Volume Set, 5th Edition (Bolton & Nouri), Chapter 145

Principles of Wound Dressings

• Maintaining a moist environment that supports epidermal cell migration
• Preserving growth factors and matrix materials at the wound surface
• Maintaining an electrical gradient that promotes healing
• Reducing scar formation through occlusion

Classification Framework

By Position Relative to the Wound

By Dressing Technique (Layered Construction)

1. Contact/interface layer — non-adherent, fluid-permeable; makes direct wound contact
2. Absorbent layer — cotton pad or gauze; wicks and retains wound exudate
3. Outer wrap/tape — secures the construct

1. Traditional Dressings (Gauze-Based)

• Inexpensive and widely available
• Limited moisture-retentive capacity
• May adhere to wound — painful removal
• Requires frequent changes (cost of nursing care)

• White petrolatum, soft paraffin wax (e.g., Vaseline® gauze, Adaptic™, Aquaphor® gauze)
• Less adherent; can be molded into wound depressions
• Examples with antimicrobials: povidone-iodine (Betadine®), silver sulfadiazine, framycetin, chlorhexidine, bismuth tribromophenate (Xeroform™)
• Tulle gras (balsam of Peru) — used in Europe for malodorous wounds

2. Moisture-Retentive (Modern) Dressings

A. Film Dressings

• Composition: Thin semipermeable polyurethane membrane
• Properties: Transparent, water vapor–permeable, impermeable to bacteria and water
• Uses: IV sites, skin tears, donor sites, superficial wounds, skin graft fixation
• Advantages: Painless; creates bacterial barrier; allows wound inspection
• Limitations: Non-absorbent; cannot handle significant exudate; may macerate wound edges
• Examples: Bioclusive™, Tegaderm™, OpSite™

B. Foam Dressings

• Composition: Polyurethane or silicone foam (adherent and non-adherent forms)
• Properties: Semipermeable; highly absorbent; thermally insulating; conforms to wound shape
• Uses: Moderate-to-heavily exuding wounds; skin grafts; venous leg ulcers; donor sites
• Advantages: Comfortable; deformable; protects from trauma
• Limitations: Cannot be used on dry wounds; may cause drying of low-exudate wounds
• Examples: Allevyn™, Biatain™, Mepilex™, PolyMem™, CuraFoam™

C. Hydrogel Dressings

• Composition: Hydrophilic sheets, gel forms, or impregnated dressings (water content 80–99%)
• Properties: Donate moisture to dry wounds; cooling and soothing effect
• Uses: Dry wounds, superficial burns, laser resurfacing, chemical peels, partial-thickness wounds, necrotic tissue (promotes autolytic debridement)
• Advantages: Non-adherent; reduces postoperative pain and inflammation; reported benefit for pruritus; accelerates healing vs. gauze
• Limitations: Slow absorption; requires secondary dressing; caution in oedematous wounds
• Examples: Aquagel™, Vigilon™, Carrasyn™, Flexigel™

D. Hydrocolloid Dressings

• Composition: Gel-forming agents (carboxymethylcellulose, pectin, gelatin) on a backing
• Properties: Occlusive to semi-occlusive; absorb exudate and form a gel over the wound
• Uses: Partial-thickness wounds, chronic ulcers (venous, diabetic), pressure injuries
• Advantages: Waterproof; self-adhering; promotes autolytic debridement; can remain in place several days
• Limitations: Not suitable for infected wounds; may have unpleasant appearance/odor on removal
• Examples: DuoDERM™, Comfeel™, Replicare™

E. Alginate Dressings

• Composition: Derived from calcium/sodium salts of alginic acid (seaweed); available as sheets or rope
• Properties: Highly absorbent; on contact with wound exudate, exchange Na⁺ for Ca²⁺ and form a gel
• Uses: Heavily exuding wounds, cavity wounds, split-thickness graft donor sites; also have hemostatic properties
• Advantages: Hemostatic; highly absorptive; non-adhesive; can be packed into cavities
• Limitations: Requires secondary dressing; gel can have unpleasant appearance; mild burning on application
• Examples: Kaltostat™, Sorbsan™, Algiderm™

F. Gelling Fiber / Hydrofiber Dressings

• Composition: Hydroentangled carboxymethylcellulose or pectin fibers
• Properties: Absorb fluid and convert to a gel; lock moisture within the fiber structure
• Uses: Heavily exuding wounds; infected wounds
• Examples: Aquacel™ (and Aquacel Ag™ with silver)

G. Superabsorbent Dressings

• Composition: Superabsorbent polymer core
• Uses: Very high-exudate wounds (e.g., large leg ulcers, lymphorrhea)
• Can absorb several times their own weight in fluid

3. Dressings Containing Antimicrobial Agents

Silver Dressings

• Silver ions bind bacterial DNA/RNA, alter cell walls and nuclear membranes
• Anti-inflammatory; decreases MMPs (upregulated in non-healing wounds)
• Nanocrystalline silver (e.g., Acticoat™) releases antibacterial silver for 3–7 days
• Active against MRSA and VRE
• Cochrane review: no significantly higher healing rates — short-term use is optimal
• Examples: Silvercel™, Acticoat™ Flex 7, PolyMem® MAX® Silver, Mepilex® Ag

Iodine Dressings

• Broad-spectrum antiseptic
• Povidone-iodine (traditional): can inhibit wound healing — now less preferred
• Cadexomer-iodine (e.g., Iodosorb™): dextran bead lattice slowly releases iodine; 1 g absorbs up to 7 ml exudate; non-cytotoxic; proven benefit in venous leg ulcers
• ⚠️ Iodine is absorbed systemically — avoid in thyroid disease, pregnancy, lactation, young children

Chlorhexidine Dressings

• Biguanide; disrupts cytoplasmic membranes of Gram-positive, Gram-negative bacteria, yeasts, molds
• PHMB (polyhexamethylene biguanide) — safer derivative added to gauze, foam, hydrogel dressings
• ⚠️ Cytotoxic to cornea, inner ear, cartilage — avoid near these structures

Honey Dressings (Manuka Honey)

• High osmolality inhibits bacterial water availability
• Contains flavonoids and aromatic acids with antimicrobial properties
• Anti-odor effect via lowered wound pH
• Releases H₂O₂ and glucuronic acid → stimulates macrophages, promotes inflammatory cytokine production

Copper Oxide / Methylene Blue + Gentian Violet

• Additional antimicrobial options available in specialized dressings

4. Dressing Selection by Wound Characteristics

5. Biological / Advanced Dressings

• Collagen dressings: Provide structural scaffold; promote cellular migration; used in chronic wounds
• Growth factor dressings: PDGF-BB (becaplermin/Regranex™) — only FDA-approved growth factor for diabetic foot ulcers (limited efficacy in practice)
• Skin substitutes / bioengineered grafts: Used in complex chronic wounds where conventional dressings fail

Key Takeaway