perhaps

If your bulla or blister needs to be drained, you should have a doctor perform the procedure. This will lower your risk of infection.

During your visit, your doctor will likely swab the area with alcohol to remove any dirt or bacteria. Then he or she will puncture your blister using a sterile needle.


http://www.healthline.com/health/bullae#Treatment4



Treatment for bullae

The following treatment is appropriate if bullae are present:

• Use compresses with Burow solution (10% aluminum acetate) in a 1:40 dilution until bullae resolve (usually within a few days)


• Compresses with a 1:10.000 solution of potassium permanganate are also effective


• Drain large bullae with a sterile syringe, and leave the roof intact


• Prescribe systemic antibiotics that cover Staphylococcus aureus and group A streptococci


http://emedicine.medscape.com/article/1122527-treatment



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Note added at 41 mins (2015-12-15 15:21:37 GMT)
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Why 'ontlasten' for that matter.

'ontlasten' may refer to 'relieving the pressure'

drainage of fluid can relieve pressure

so you might also opt for:

relieve pressure with a sterile syringe

or so

http://tinyurl.com/gudbhlp


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Note added at 45 mins (2015-12-15 15:25:54 GMT)
--------------------------------------------------

Why 'ontlasten' for that matter?

'ontlasten my refer to relieving the pressure

drainage of fluid can relieve pressure

So you might also opt for something like': relieve the pressure inside bullae by draining them with a sterile syringe

or so



http://tinyurl.com/gudbhlp

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Note added at 47 mins (2015-12-15 15:27:54 GMT)
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Or: relieve pressure inside the bullae by draining them with a sterile syringe

or so