Differential Diagnosis for Fluid Filled Blister Caused by Trauma on the Buttocks

• Single Most Likely Diagnosis
  • Pressure ulcer (also known as bedsore or decubitus ulcer): This is the most likely diagnosis given the location on the buttocks and the history of trauma, which could imply prolonged pressure on the area.
• Other Likely Diagnoses
  • Friction blister: Caused by friction and shear forces, common in areas subjected to repetitive motion or pressure, such as the buttocks.
  • Burn blister: If the trauma involved heat or a caustic substance, a burn blister could be a consideration, though the context suggests this is less likely.
  • Infectious blister (e.g., caused by Staphylococcus aureus or Streptococcus pyogenes): Bacterial infections can cause blisters, especially if the skin is compromised.
• Do Not Miss Diagnoses
  • Necrotizing fasciitis: Although rare, this is a life-threatening condition that can be triggered by trauma and initially presents with symptoms that might seem benign, such as a blister or swelling.
  • Gas gangrene: Caused by Clostridium perfringens, this condition can arise from traumatic wounds and is characterized by gas production in tissues, leading to severe swelling and potentially life-threatening complications.
• Rare Diagnoses
  • Epidermolysis bullosa acquisita: An autoimmune disease that can cause blistering of the skin in response to trauma.
  • Bullous pemphigoid: Another autoimmune condition that results in blistering of the skin, which could potentially be triggered or exacerbated by trauma.
  • Dermatitis herpetiformis: An autoimmune skin condition characterized by blisters, though it's less directly associated with trauma and more with gluten sensitivity.