Terminology for Fluid-Filled Burn Blisters
The proper medical term for a fluid-filled blister after a burn is simply a "blister" (for lesions up to approximately 1 cm) or "bulla" (for lesions larger than approximately 1 cm). 1
Specific Terminology
- Blisters/blebs refer to circumscribed collections of fluid in the skin measuring roughly up to 1 cm in diameter 1
- Bullae (singular: bulla) refer to fluid-filled lesions measuring roughly 1 cm or larger in diameter 1
- These fluid-filled structures are characteristic findings of second-degree superficial burns 2
Anatomical Classification
The location of fluid accumulation within the skin layers can be further specified:
- Intra-epidermal blisters occur within the epidermis itself 1
- Subepidermal blisters form beneath the epidermis 1
- In burn injuries, the blister typically forms between the epidermis and dermis as the damaged epidermis separates from underlying tissue 3, 4
Composition of Burn Blister Fluid
- The fluid within burn blisters is an ultrafiltrate of plasma that is rich in proteins including immunoglobulins, various cytokines, prostaglandins, and interleukins 2
- This fluid contains numerous molecules related to wound healing and reflects the state of the local tissue microenvironment 5
Clinical Context
Important distinction: If the blister contains pus rather than clear or serosanguinous fluid, it should be termed a pustule, which indicates infection 1. This distinction is critical because it changes management—pustules require antimicrobial therapy while simple blisters do not 3, 4.