How long to wait after hyalase (hyaluronidase) injection before reinjecting with another hyaluronic acid filler?

Optimal Timing for Hyaluronic Acid Filler Reinjection After Hyaluronidase

Hyaluronic acid fillers should be reinjected 6 hours after hyaluronidase injection to ensure successful engraftment and optimal results. 1

Evidence-Based Timing for Reinjection

The timing of hyaluronic acid (HA) filler reinjection after hyaluronidase administration is critical for achieving successful outcomes. The most recent and highest quality research provides clear guidance:

• A study specifically examining this question found that hyaluronidase loses its effect in dermis and subcutaneous tissue within 3-6 hours after injection 1
• At 6 hours post-hyaluronidase, reinjected HA filler materials restored almost their original volume with no significant differences from positive controls 1
• By 3 hours post-reinjection, filler material became evident again, but full restoration of shape and volume was observed at the 6-hour mark 1

Clinical Considerations for Reinjection

Anatomical Considerations

• When reinjecting in the periorbital area, use a 22G x 2 inches (~5 cm) cannula for safety 2
• For lateral facial lifting, place filler on periosteum or deep subcutaneous plane to create strategic support points 2
• Inject small amounts (0.2-0.5 mL per quadrant) in a retrograde fashion above the orbicularis oculi muscle 2

Safety Precautions

• Be aware that complications from HA fillers can occur even years after injection, as seen in a case of chronic eyelid edema and xerophthalmia that developed two months after periorbital injection and persisted for two years 3
• Understand that different HA fillers show comparable susceptibility to hyaluronidase-mediated degradation, with all studied fillers showing rapid decrease in volume within 24 hours of hyaluronidase injection 4

Special Circumstances

For Vascular Complications

• If a vascular event occurs, implement a High Dose Pulsed Hyaluronidase (HDPH) protocol immediately 5
• This involves repeated administration of high doses of hyaluronidase into the ischemic tissue hourly until clinical resolution (improved capillary refill, skin color, and absence of pain) 5
• This protocol has proven successful when implemented within 2 days of ischemic event onset 5

For Fillers with Longer Residence Time

• HA fillers with prolonged residence time (3+ months) may require higher doses of hyaluronidase for efficient degradation due to tissue integration 4
• After complete degradation is achieved, still wait the standard 6 hours before reinjection 1

Common Pitfalls to Avoid

1. Reinjecting too early: Reinjecting before 6 hours can result in immediate degradation of the new filler by residual hyaluronidase activity
2. Ignoring anatomical danger zones: Particularly in periorbital areas where complications can be severe and long-lasting 3
3. Failing to adjust technique based on previous complications: If a patient experienced complications with previous injections, consider modified approaches or alternative treatment options
4. Not preparing for potential vascular events: Always have hyaluronidase readily available when performing HA filler injections 5

By following these evidence-based guidelines and waiting 6 hours after hyaluronidase injection before reinjecting HA filler, practitioners can achieve optimal outcomes while minimizing complications.