Understanding Hyaluronidase Use in Dermal Filler Dissolution and the Risk of Posthyaluronidase Syndrome

Hyaluronic acid (HA) dermal fillers are a cornerstone in aesthetic medicine, particularly for enhancing facial volume and addressing signs of aging. However, as filler use grows, so do the complications that accompany them, especially in sensitive areas like the periocular region. A recent study sheds light on how hyaluronidase, an enzyme used to dissolve unwanted filler, impacts treatment outcomes and reveals insights into a phenomenon known as posthyaluronidase syndrome.

The Role of Hyaluronidase in Aesthetic Medicine

Hyaluronidase is commonly used to dissolve HA fillers when complications such as swelling, lumpiness, or migration occur. It is also utilized before surgical procedures, such as blepharoplasty, to remove fillers that might interfere with surgery. Despite its widespread use, there is no standardized protocol for the optimal concentration or dose of hyaluronidase, and outcomes can vary significantly.

Complications Associated with Dermal Fillers

Complications from dermal fillers can range from mild to severe, with the periocular area being particularly vulnerable due to its delicate tissue structure. Among the most serious risks is vision loss, though this remains rare. More commonly, patients experience swelling, lumpiness, and filler migration. When these issues arise, hyaluronidase is often used to resolve them. However, patients and practitioners must be aware of the risks associated with its use, particularly the development of posthyaluronidase syndrome.

What is Posthyaluronidase Syndrome?

Posthyaluronidase syndrome refers to negative aesthetic outcomes following hyaluronidase treatment. These outcomes can include hollowing of the facial tissues, loss of skin elasticity, and discoloration, leading to a deterioration in appearance worse than before treatment. This phenomenon was observed in approximately 18% of patients treated with hyaluronidase to dissolve fillers.

Interestingly, the study found that the syndrome was significantly correlated with the volume of filler and the length of time the filler had been in place, rather than the concentration or dose of hyaluronidase used. Patients with larger volumes of filler or fillers that had been in situ for longer periods were more likely to experience hollowing and other adverse effects.

Dosing Strategies for Hyaluronidase

The study examined different concentrations of hyaluronidase and their impact on treatment outcomes. The most frequently used concentrations were 150 U/mL and 75 U/mL, with no significant differences in the rates of satisfactory results or posthyaluronidase syndrome between these groups. However, lower concentrations (37.5 U/mL) were associated with insufficient treatment, highlighting the need for appropriate dosing.

For every 0.1 mL of filler, an average of 35 units of hyaluronidase was used, although the exact dose varied based on the patient’s specific needs and the volume of filler present. Despite this variability, the overall rate of satisfactory outcomes was 59%, with 24% of cases requiring additional treatment.

Key Takeaways for Practitioners and Patients

• Personalized Approach: Each patient’s treatment should be personalized, taking into account the amount of filler, its location, and how long it has been in place.
• Informed Consent: It is crucial to inform patients about the risk of posthyaluronidase syndrome, especially those with large filler volumes or long filler histories.
• Ongoing Research: Further studies are needed to fully understand the long-term effects of fillers and hyaluronidase on facial tissues, and to develop standardized protocols for hyaluronidase use.

While hyaluronidase is a valuable tool in the dissolution of HA fillers, practitioners must remain vigilant about the potential for adverse effects. By understanding the factors that influence outcomes, both practitioners and patients can make informed decisions to achieve the best aesthetic results while minimizing risks.

Wilde CL, Jiang K, Lee S, Ezra DG. The Posthyaluronidase Syndrome: Dosing Strategies for Hyaluronidase in the Dissolving of Facial Filler and Independent Predictors of Poor Outcomes. Plast Reconstr Surg Glob Open. 2024 Apr 23;12(4):e5765. doi: 10.1097/GOX.0000000000005765. PMID: 38655103; PMCID: PMC11037726.