Key facts
- What happens
- Filler enters or compresses an artery and the tissue it supplies loses its blood flow
- Warning signs
- Blanching, dusky or net-like mottled discolouration, and pain that is severe or worsening rather than settling
- Emergency signs
- Any change in vision, stroke-like weakness or slurred speech: go to A&E or call 995
- Treatment
- Urgent high-dose hyaluronidase for hyaluronic acid filler, repeated and reassessed; non-HA fillers have no dissolving option
- Higher-risk zones
- The nose, glabella, forehead and tear trough, where arteries connect with the circulation of the eye
What is a vascular occlusion?
A vascular occlusion happens when injected filler blocks an artery from inside, or presses on it from outside, so that blood stops reaching the skin the vessel supplies. Within minutes to hours the area blanches, then turns dusky, purple or net-like as the tissue is starved of oxygen, and pain is typically out of proportion to what an injection should cause. Left untreated, the skin can break down and scar.
In the rarest cases, filler forced into a branch of the facial arteries travels backwards into the circulation of the eye. The result can be sudden visual blurring, loss of vision or pain in or around the eye, and it is why the nose, glabella, forehead and tear trough are treated as the highest-risk zones. World literature reviews have catalogued these events to identify the sites and techniques involved, and that evidence shapes how fillers are placed.
How is it recognised and treated?
Recognition is the first treatment. Swelling, tenderness and some bruising after filler are expected; skin that turns white or mottled, or pain that is getting worse rather than settling in the hours or days after injection, is different in kind and needs same-day medical assessment, whether with the clinic that injected you or another doctor. Any change in vision is an emergency: go to the nearest hospital emergency department, or call 995, rather than travelling to a clinic first.
For hyaluronic acid filler, the treatment is hyaluronidase, an enzyme that breaks down the gel. Published guidelines describe a high-dose, repeated protocol for suspected occlusion, flooding the affected area and reassessing at intervals until the skin colour and capillary refill recover. It is kept in the room wherever hyaluronic acid is injected. Hyaluronidase has no action on calcium hydroxylapatite, polycaprolactone or poly-L-lactic acid, which is one reason hyaluronic acid is favoured in the highest-risk zones and why non-HA products are placed conservatively.
“Hyaluronidase dissolves hyaluronic acid and nothing else. If someone offers to dissolve Ellanse or Sculptra, they are describing something that does not happen.”
Dr Sin YongOn what hyaluronidase can and cannot reverse
What is it often confused with?
A bruise is the usual confusion. A bruise is blue or purple, appears where the needle entered, is tender but not disproportionately painful, and the skin over it still blanches and refills normally when pressed. An occlusion blanches without pressure, often follows the territory of an artery rather than the injection point, and hurts more than it should. Normal post-injection swelling settles; occlusion worsens.
It is also different from the Tyndall effect, a bluish tint where hyaluronic acid sits too superficially, and from a late inflammatory nodule, both of which are managed on their own timelines and are not emergencies. Dissolving filler for aesthetic reasons, as described on the filler correction page, is planned and staged; dissolving for a suspected occlusion is immediate, high-dose and repeated. The same enzyme, used for different reasons at different speeds.
How is the risk reduced before it happens?
Risk is reduced by anatomy and technique rather than by any product promise. Knowing where the facial arteries run and how deep, placing product in the planned plane in small increments with low pressure, using a blunt cannula where it suits the area, and choosing hyaluronic acid where reversibility matters all lower the chance of an event. For the nose bridge, where Dr Sin Yong usually works with calcium hydroxylapatite or polycaprolactone, placement and quantity are planned conservatively because those products cannot be dissolved.
No technique removes the risk entirely, which is why a doctor who injects filler should also be able to recognise and treat an occlusion, keep hyaluronidase to hand and tell patients which signs to report. The warning signs follow the same rules wherever you were treated: blanching, mottling or worsening pain mean same-day assessment, and any vision change means the emergency department. The practice's complication care page sets out exactly what to do and whom to contact.
