How do I manage an intact blister?

Management of an Intact Blister

Intact blisters should generally be left in place, but if they are large, painful, or in areas that interfere with function, they should be punctured at the base with a sterile needle, drained while leaving the blister roof intact, and covered with a sterile dressing. 1

Assessment and Decision Algorithm

When managing an intact blister, follow this approach:

1. Assess the blister characteristics:

   • Size: Small, medium, or large
   • Location: Functional area (e.g., sole of foot) or non-functional area
   • Pain level: Painful or non-painful
   • Signs of infection: Redness, warmth, purulence

2. Decision tree:

   • Small to medium blisters without pain: Leave intact 1
   • Large blisters or those causing pressure pain: Puncture and drain while leaving roof intact 1
   • Blisters in functional areas (e.g., soles of feet): Puncture and drain while leaving roof intact 1, 2

Proper Blister Drainage Technique

If drainage is indicated, follow these steps 1:

1. Gently cleanse the blister with an antimicrobial solution, taking care not to rupture it
2. Pierce the blister at its base with a sterile needle, with the bevel facing up
3. Select a drainage site where fluid will drain by gravity to prevent refilling
4. Gently apply pressure with sterile gauze to facilitate drainage and absorb fluid
5. Do not remove the blister roof - it serves as a natural biological dressing
6. After drainage, gently cleanse again with an antimicrobial solution
7. Cover with a sterile, non-adherent dressing

Post-Drainage Care

After draining the blister 1:

• Apply a bland emollient to support barrier function and encourage re-epithelialization
• Monitor for signs of infection (increased redness, warmth, pain, purulence)
• Change dressings using aseptic technique
• Consider topical antimicrobials only if signs of infection develop

Special Considerations

• Pain management: Many patients report pain during blister care; offer appropriate analgesia before the procedure 1
• Large blisters: May need multiple puncture sites or a larger needle for adequate drainage 1
• Infection risk: Monitor carefully as infection can increase scarring risk and delay healing 1
• Burn blisters: These require special consideration and may need different management approaches 1, 2

Common Pitfalls to Avoid

1. Do not remove the blister roof - this increases infection risk and delays healing 1
2. Do not apply ice directly to blisters - it can cause tissue ischemia 1
3. Do not use adhesive dressings directly on the blister - use non-adherent dressings instead 1
4. Do not ignore signs of infection - if present, seek medical attention promptly

The evidence strongly supports preserving the blister roof as it provides the best protection against infection and promotes optimal healing while reducing pain 1, 2.