Skin - nontumor
Blistering disorders
Blood blister

Author: Narina Grove, M.D., M.A. (see Authors page)

Revised: 21 October 2016, last major update June 2016

Copyright: (c) 2003-2016,, Inc.

PubMed Search: Blood blister [title]
Cite this page: Blood blister. website. Accessed October 27th, 2016.
Definition / General
  • Essentially identical to friction blister with the extension of cytolysis through the basal layer resulting in a hemorrhagic blister
  • Intraepidermal cleavage due to cytolysis and necrosis of keratinocytes in the upper stratum malpighii
  • Friction blister: blister caused by shearing force, which subsequently fills with clear fluid
  • Blood blister: blister caused by excessive force, which fills with blood
  • Hemorrhagic bullae: larger blisters (> 0.5 cm), often multiple and associated with underlying disease process, and more often deeper (suprabasilar or subepidermal)
  • Common in athletes, dancers or those wearing poorly fitting shoes
  • Associated with manual labor
  • Hands and feet; sites subjected to repetitive friction
  • Shearing forces within the epidermis cause friction blisters in the areas where epidermis is thick and firmly attached to the underlying tissue
  • Prolonged walking or repetitive actions
Diagrams / Tables

Images hosted on other servers:

Friction Blister

Clinical Features
  • Hemorrhagic blister usually occurring on exposed skin
  • Most commonly occurring on hands and feet
  • Typically, a clinical diagnosis
  • If solitary, diagnosis is usually a simple blood blister, rarely biopsied
  • Multiple blood blisters of unknown origin may indicate an underlying process (see "differential diagnosis" below)
  • Symptomatic treatment
Clinical Images

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Blood blisters

Gross Description
  • Cutaneous vesicle or bulla filled with sanguinous fluid
Micro Description
  • Intraepidermal split
  • The roof of the blister is composed of the stratum corneum, variable stratum granulosum and amorphous cellular debris
  • Most of the degenerated keratinocytes are pale and are located at the floor of the cleft
  • The deeper part of the epidermis consists of undamaged cells
  • In severe cases, the cytolysis may extend through the basal layer leading to hemorrhagic blisters
Micro Images

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Compact orthokeratosis of volar skin

Friction blister
Electron Microscopy Description
  • Clumped tonofilaments, intracellular edema, small vacuoles at the cell periphery, areas devoid of organelles
Differential Diagnosis