The Use of Hyaluronidase in Aesthetic Practice
There are several sources of hyaluronidase and they are generally divided into 3 subgroups (Meyer7), mammalian (obtained from the testis), hookworm/leech and microbial although recombinant human hyaluronidase is now available (Hylenex, from Halozyme Therapeutics, San Diego, California) which has a purity of 100 times higher than some currently used Bovine preparations8. There are no long-term data for this product yet, but it is likely to have a lower proportion of allergic reactions.
This guidance refers to the use of Hyalase® (Wockhardt) which is readily available in the UK as a 1500-unit ampoule of powder for reconstitution and is of ovine (sheep) origin.
Off-label use of hyaluronidase
Although hyaluronidase is not licensed for the use in correcting problems with dermal filler injections and off-label promotion is not allowed by Article 87 of Directive 2001/83/EC, its use is allowed provided the patient’s best interest and autonomy are respected and forms part of the informed consent (MHRA, 2009).
What should be treated?
Vascular compromise as a result of hyaluronic acid filler injection should be treated immediately (refer to Aesthetic Complications Expert Group, Necrosis guidance). Signs of impending necrosis include pain, prolonged blanching (reticulated white or dusky appearance of the skin) and coolness of the skin. Hyaluronidase should be administered as soon as this complication occurs, there is good evidence that tissue necrosis will be prevented or be less severe the sooner the hyaluronidase is injected5.
The Tyndall effect refers to the scattering of light that may be seen in some patients after injection of hyaluronic acid resulting in a bluish hue of the skin (refer to Aesthetic Complications Expert Group, Tyndall’s effect guidance). It is often caused by injecting too
©Aesthetic Complications Expert Group, the Use of Hyaluronidase in Aesthetic Practice, Page 3 of 9
Superficially, placing large boluses of product in one area or using an inappropriate product for the area treated. It is most commonly seen in the sub ocular region. By degrading the hyaluronic acid using hyaluronidase, this problem can usually be corrected.
Overcorrection or misplacement of hyaluronic acid filler can be successfully treated with hyaluronidase although this is often caused by poor injection technique or poor choice of product for a particular area.
Lumps or nodules that may appear several months after the initial treatment may be amenable to hyaluronidase (refer to Aesthetic Complications Expert Group, Delayed Onset Nodules guidance). It is important to remember that hyaluronidase is used to help diffuse fluids intradermal and for hypodermoclysis so if the nodule is thought to be infective, it is important to administer antibiotics to prevent further spread of infection (refer to Aesthetic Complications Expert Group, Infection guidance).