November 4, 2019

The occurrence of vascular occlusion (VO) after dermal filler should be exceedingly rare- even busy injectors can go many years without seeing one.

This is why when they do occur, mistakes are easily made.

Over many years of supporting clinicians and patients with suspected vascular occlusions, I have noticed several common diagnostic mistakes clinicians make which can make matters much worse.


Diagnostic errors are probably where the most significant errors can arise.

The bulk of these mistakes centre around poor examination or interpretation of capillary refill time (CRT).

In this article, I will explain how poor examination causes unnecessary risk to patients, and how you can improve diagnostic accuracy in the event of a suspected occlusion with some simple tweaks to the process.


When I faced my first occlusion I remember grasping for certainty at the diagnostic stage and being confused by the different times I could get as I tested the CRT.

I discovered sometimes CRT would appear normal, giving a false reassurance but other times there was a clear delay.

Through repetition, as I investigated the suspect occlusion, I discovered a technique that made the apparent disruption of blood flow shift from subtle to obvious.

Problem is we don’t get long to get this right. The first few hours are critical.


Even experienced clinicians can go years between occlusions, so many colleagues like to get a second opinion on the issue to confirm a VO or reassure.

Problem is, getting this from colleagues over WhatsApp or social media, with often badly lit video footage and no guarantee how experienced the advisors are, is risky.

You may be falsely reassured or an incorrect diagnosis of VO made,  leading to a lack of action, or unnecessary reversals and associated risks.

You must, therefore, get clear on how to do this test well yourself.

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  1. Compress more than just the area you injected – use a full finger or the flat of the hand to compress as much as possible around the suspect area.  This allows you to clearly see the capillaries around the site fill up with blood on release, and this makes the contrast with the occluded site much easier to see.
  2. Use a control- If the occlusion is near the midline, especially in lips, use the other side as a control.   Compress both sides and watch the flow of blood- the difference in lips is usually stark if there is an occlusion.
  3. Compress firmly-  light touches leave more blood in the skin and the contrast is therefore poor- a firm compress is important to increase sensitivity by expelling as much blood as possible from the skin in question before seeing if it refills quickly or not.
  4. Give your compression enough time-  A compression of 4 to 5 seconds is essential, as it takes time for blood to leave the area while you apply pressure, and the more empty the area the more obvious delayed CRT becomes.  Short compressions make it harder to measure CRT.
  5. Be aware of the overdiagnosis of VO

I suspect overdiagnosis of vascular occlusions is common and has its own risk of anaphylactic shock (just one of the reasons why allergy testing may be justified prior to urgent reversals).

The typical scenario in which overdiagnosis occurs is in the presence of a haematoma in an anxious patient, representing hours after the procedure.

This scenario often triggers anxiety in the injector and a slight delay in CRT is sufficient to confuse inexperienced clinicians and result in an unnecessary emergency reversal.

The cases I have seen appear to occur when the patient represents 18 to 24-hours post-procedure with a haematoma and delayed CRT which was not apparent immediately post-procedure.

The inexperienced and anxious injector focuses only on the delay and does not take into account the bigger picture, including time since the injection, initial normal CRT and the lack of pain at representation.

Written by:

Dr Tim Pearce


Dr Tim qualified in medicine in 2006 following his studies at Warwick and Leeds universities.

He founded SkinViva & SkinViva Training.

Dr Tim has been an Aesthetic Doctor for over 11 years, as well as being an active practicing GP.

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