What is the treatment for a large blister?

Treatment of Large Blisters

For large blisters, the recommended treatment is to pierce the blister at its base with a sterile needle (bevel facing up), drain the fluid while leaving the blister roof intact as a biological dressing, then gently cleanse with an antimicrobial solution and apply a bland emollient. 1

Step-by-Step Management Protocol

Initial Assessment

• Determine if the blister is:
  • Uncomplicated (no signs of infection)
  • Painful/pressure-causing
  • Already ruptured
  • Showing signs of infection (increasing redness, warmth, pain, pus)

Treatment Algorithm

1. For intact large blisters:

   • Gently cleanse with antimicrobial solution 1
   • Pierce at the base with a sterile needle (bevel facing up) 1
   • Select a site where fluid will drain by gravity to prevent refilling 1
   • For very large blisters, use a larger needle and pierce more than once 1
   • Apply gentle pressure with sterile gauze to facilitate drainage 1
   • Do not remove the blister roof (leave it in place as a biological dressing) 1, 2

2. After drainage:

   • Cleanse again with antimicrobial solution 1
   • Apply bland emollient (50% white soft paraffin and 50% liquid paraffin recommended) 1
   • Apply non-adherent dressing if necessary 1

3. Special circumstances:

   • For ruptured blisters without infection signs: leave remnants of blister roof in place 2
   • For ruptured blisters with infection signs: remove remnants of blister roof 2
   • For burn blisters (grade 2a or higher): remove blister roof 2

Pain Management

• Offer analgesia prior to starting the procedure, as many patients report pain or burning sensation during blister care 1
• Consider over-the-counter pain relievers like acetaminophen or NSAIDs as needed 3

Infection Prevention

• Daily washing with antibacterial products to decrease colonization 1
• Change dressings using aseptic technique 1
• Monitor for signs of infection (redness, warmth, pain, pus, red streaks) 3

When to Seek Medical Attention

• If signs of infection develop 3
• If the blister covers >30% body surface area 3
• If the blister involves mucous membranes 3

Antibiotic Treatment (if infection develops)

• Oral antibiotics recommended by the Infectious Diseases Society of America: 3
  • Dicloxacillin: 250 mg four times daily
  • Cephalexin: 250 mg four times daily
  • Clindamycin: 300-400 mg three times daily (if penicillin allergic)
  • Amoxicillin/clavulanate: 875/125 mg twice daily

Common Pitfalls to Avoid

• Removing the blister roof unnecessarily (increases infection risk and delays healing) 1, 2
• Using adhesive dressings that stick to the wound bed (damages new epithelial cells) 3
• Failing to provide adequate pain management before procedures 1
• Neglecting to monitor for signs of infection 1, 3

The Initiative Chronic Wounds (ICW) consensus emphasizes that there is no single correct approach for all blisters - treatment should be based on individual factors including the cause of the blister, location, and whether infection is present 2. However, for most large uncomplicated blisters, the evidence supports draining while preserving the blister roof as the optimal approach for promoting healing and preventing infection.