The best replacement for bullae is bleb.

The best alternatives to bullae are rated as following:
★★★★★  bleb
★★★★  blebs
★★★  vesicle
★★  pneumothorax
★  bullae
★  vesicles
★  bulla
  blister
  bullous
  subpleural blebs

Your alternative for bullae is not listed? Suggest!
Speaking about bullae, one probably shouldn't forget about cellulitis.

Other search terms related to bullae and their ratings are:
★★★★★ cellulitis
You have in mind a companion for bullae and it is not yet here? Propose!



Google Trends

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bullae
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