Hyaluronic acid (HA) is a naturally occurring substance found in skin and joints. The majority of dermal fillers injected worldwide are comprised of HA. One of the major appeals of the HA fillers is that they are reversible and are temporary. Hyaluronidase, an enzyme found across many species, is the “antidote” used to dissolve the HA fillers. The following conditions are appropriate to use hyaluronidase:
- Undesired cosmetic result
- Infected filler
- Vascular compromise (emergency)
- Blindness (emergency)
While there are a many variations of hyaluronidase available in the US (Hylenex, Hydase, Vitrase, Amphadase), the preferred brand at The Aesthetic Clinique is Hylenex. The reason to choose Hylenex is because it is a human recombinant form and is the least likely to have an allergic/anaphylaxis reaction.
Treating filler with Hylenex is not an exact science. There are huge variations in the amount of Hylenex required to dissolve a filler. The important factors to consider are:
- Degree of crosslinking (higher crosslinked fillers are harder to dissolve)
- Time filler has been in body (longer time equates to harder to dissolve)
- Urgency (higher doses are required to resolve emergency situations – in general)
- Inflammatory granuloma or nodules require higher doses
- Individual variations
A typical Hylenex treatment is less than 5 minutes and very comfortable. The Hylenex is often mixed with lidocaine to improve comfort and leaves the area numb for about 30 minutes. The HA is dissolved within a few hours (sometimes minutes) but there will be some swelling from the injection that can take a day or 2 to resolve. If replacement of filler is desired, this can be performed in 3 days. Likewise, if further treatment is required (in a non-emergency situation), repeat injections are done at 3 days or later.