Hyaluronic acid fillers are among the most common aesthetic treatments worldwide. In most cases they go smoothly. The most feared complication, however, is vascular occlusion: if filler enters a blood vessel or compresses it from the outside, tissue can die – in the worst case, blindness can result. Recent reviews from 2025 and 2026 summarise how to prevent it and how to respond in an emergency.
Why is this dangerous?
Many arteries in the face are connected to one another – including with the vessels that supply the eye. If filler is injected into an artery under pressure, it can spread against the direction of blood flow and cause a blockage elsewhere. Areas considered particularly high-risk include the glabella (frown line), the nose, the nasolabial fold and the temples.
Warning signs – report them immediately!
- sudden, severe pain during or after the injection (may be masked by anaesthetic in the filler)
- noticeable blanching or white patches on the skin
- later, a bluish-purple, net-like discolouration (livedo)
- delayed capillary refill after pressure on the skin
- visual disturbances, eye pain, double vision, headache or dizziness – an absolute emergency
Emergency treatment
The advantage of hyaluronic acid fillers is that they can be dissolved with the enzyme hyaluronidase. The so-called high-dose pulsed hyaluronidase protocol (HDPH), described by DeLorenzi in 2017, has become established. The enzyme is injected over a wide area within the affected vascular territory – typically 450–1,500 units per round, repeated hourly, combined with warm compresses and massage. Perfusion is reassessed roughly every 20 minutes until the skin returns to its normal colour.
If vision is affected, every minute counts: expert groups stress that blood flow should be restored within about 60 to 90 minutes and that immediate referral to ophthalmology is necessary. Injections behind the eye (retrobulbar) remain reserved for experienced specialists. Nitroglycerin patches, which were often used in the past, are no longer recommended.
Prevention: what patients can look out for
- Treatment by a doctor: only have fillers injected by doctors with sound anatomical training.
- Emergency equipment: ask whether hyaluronidase is kept in stock at the practice and whether there is an emergency plan.
- Technique: slow injection at low pressure, small volumes, blunt cannulas in high-risk zones where appropriate, and ultrasound guidance reduce the risk.
- Availability: the practice should be reachable after the treatment – complications can also occur hours later.
One problem: the availability of hyaluronidase
Hyaluronidase is not approved for aesthetic medicine in the EU; it is used “off-label”. In Germany, one product is approved for anaesthesia. Experts have long been calling for uniform guidelines and reliable access for emergencies.
Note: This article is for general information only and does not replace medical advice. If you notice warning signs after a filler treatment, contact your treating practice immediately or call the emergency number 112.
Sources
- Papagni M. F. et al.: Hyaluronidase Use in Aesthetic Medicine: Formulations, Safety, and Clinical Practice. J Clin Med 2026, 15(1), 279
- Lowe et al.: Hyaluronic Acid Dermal Filler-Associated Vascular Occlusion – A Review of Prevention and Management Strategies. J Cosmet Dermatol 2026
- Aesthetic Plastic Surgery (2026): Guide for Managing Vascular Occlusion Due to Fillers with Extended Neuro-Ophthalmic Involvement
