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Coma bullae in Adult
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Coma bullae in Adult

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Contributors: Aman Samrao MD, Belinda Tan MD, PhD, Whitney A. High MD, JD, MEng
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Coma bullae are typically large bullae that are caused by physical forces.

They occur in comatose or immobile patients at points of maximum pressure and in patients with neurologic disorders. They form within 48-72 hours after the immobility. They can be skin colored or red / purple from hemorrhage. Coma bullae have been associated with barbiturate overdose.


L13.8 – Other specified bullous disorders

339008 – Blister

Look For

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

  • Epidermolysis bullosa acquisita – Patients usually have a history of blisters at multiple sites with even minimal friction. Histopathology can confirm diagnosis.
  • Epidermolysis bullosa simplex – Patients usually have a history of blisters at multiple sites on the hands and feet. Histopathology can confirm diagnosis.
  • Bullosis diabeticorum – Patients have diabetes mellitus.
  • Stasis bullae (see also stasis dermatitis) – More common symmetrically around the lower legs.
  • Lymphedema – Common in immobile hospitalized patients and found in areas of dependent edema, but not at direct points of pressure. May arise during diuresis.
  • Bullous fixed drug eruption – Round bullae, usually associated with more inflammation and red-brown plaques underlying the bullae.

Best Tests

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Management Pearls

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Drug Reaction Data

Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.

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Last Updated: 09/06/2017
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Coma bullae in Adult
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Coma bullae : Coma, Flaccid bullae, Pressure exposure, Tense bullae, Immobilized patient
Clinical image of Coma bullae
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