Dissolving Filler (Hyaluronidase): When Is It Needed, How Is It Done, and What Should You Watch Out For?

What is dissolving filler and how does it work?

An important feature of hyaluronic acid fillers is that they can be dissolved when necessary. Hyaluronidase, which is used for this, is an enzyme that breaks the long chains of hyaluronic acid into small pieces. The physician injects the enzyme with a fine needle into the area where the filler lies; the broken-down gel is cleared away by the body. There are hyaluronidase products obtained from different sources; their potency and their allergy profiles are not identical.

The questions of how the enzyme affects the body’s own hyaluronic acid and why the area may look emptier after dissolving are dealt with in detail in the article “Rumour: If filler is dissolved, your face’s own tissue dissolves too — What does the science say?”; they will not be repeated here.

When is dissolving filler needed?

The decision to dissolve arises in three separate situations: emergencies, the treatment of a medical problem, and dissatisfaction with the result. The levels of urgency are very different from one another.

How these problems arise and the treatment options other than dissolving are described in the article “Filler Complications: Swelling, Nodules, the Tyndall Effect, Late Reactions and Dissolving Filler”. When you are unhappy with the result, it is important not to decide in a hurry: part of the swelling and irregularity of the first days improves by itself. Your physician will often suggest waiting for the area to settle and then assessing it again.

Emergency use: vascular occlusion

When filler enters a blood vessel or presses on a vessel from outside, blood does not reach that area. This can lead to tissue loss in the skin and, very rarely, to loss of vision. In vascular occlusion due to hyaluronic acid filler, hyaluronidase is a fundamental part of treatment, and the aim is to give it as early as possible.

In an emergency the approach differs from planned dissolving: the physician does not wait to carry out a skin test, applies the enzyme to the whole of the affected area, repeatedly and at short intervals where necessary, and monitors you until the colour and circulation of the skin improve. The physician decides the amount to be given and the number of repeats.

For details of the symptoms and what to do step by step, see the article “After Fillers: When Is It an Emergency? Vascular Occlusion and Other Warning Signs”.

Which fillers does it work on, and which not?

Hyaluronidase breaks down hyaluronic acid only. Fillers made of calcium hydroxylapatite, poly-L-lactic acid, silicone and other substances that do not dissolve in the body cannot be dissolved with this enzyme; the treatment of problems related to these fillers is different and is described in the article “Complications of Permanent and Semi-Permanent Fillers: Silicone, Granulomas, Late Reactions and Treatment”.

Hyaluronic acid fillers are not all the same either. Denser and more tightly cross-linked gels may be more resistant to the enzyme and may require more than one treatment. For this reason, knowing which product you were given previously, when and in which area makes the procedure easier. If the type of filler is not known, your physician can make an assessment by examination and, if necessary, with methods such as ultrasound.

Who is it not suitable for, and what should you watch out for?

• In people who have previously had an allergic reaction to hyaluronidase, planned dissolving is generally not carried out.
• In people who are allergic to bee or wasp stings the risk may be higher; in these people the decision is made with greater care.
• If active infection is suspected in the area, the physician will usually assess and treat the infection first; the enzyme can make it easier for infection to spread to the surrounding tissue.
• Pregnancy and breastfeeding: data on safety are limited. Planned dissolving is mostly postponed; in emergencies the physician weighs up the benefit and risk.
• If botulinum toxin has recently been given in the same area, tell your physician; the enzyme can increase the spread of medicines in the tissue.
• Report all the medicines you take; some medicines can alter the effect of the enzyme. Do not stop any medicine on your own.

In emergencies such as vascular occlusion, most of these cautions become relative, because the risk of not treating is usually greater. This assessment is made by the physician managing the emergency.

The risk of allergy and the debate about skin testing

Because hyaluronidase is a foreign protein, it can cause an allergic reaction. Most of the reactions reported are local responses such as itching, redness and swelling at the injection site. Serious reactions such as widespread hives, swelling of the face and throat or anaphylaxis are rare, but they have been reported. A reaction may begin within minutes, or it may appear hours or days later.

Bee and wasp venom also contains hyaluronidase. For this reason it is thought that the risk of allergy to the enzyme may be higher in people who are allergic to stings. If you have such a history, be sure to mention it before the procedure.

There is no consensus among physicians on whether a skin test should be carried out before the procedure. In the test, a small amount of enzyme is given into the skin, usually on the forearm, and after a while it is checked for a raised area, redness and itching. Some guidelines recommend the test in non-emergency situations, especially in people with a history of allergy. On the other hand, the test can give false positive or false negative results and may not predict reactions that start late; in other words, a negative test does not show for certain that there will be no allergy. In emergencies, there is no waiting for a test.

Whether or not a test is carried out, it is important that the procedure is done in a healthcare facility where an allergic reaction can be dealt with immediately, and that you remain under observation for a while afterwards. For the symptoms of allergy, see the article “Allergic Reactions in Aesthetic Treatments: Symptoms from Redness to Anaphylaxis and What to Do”.

What does off-label use mean?

A medicine’s licence lists, one by one, the purposes for which it is to be used. In many countries the licensed uses of hyaluronidase cover other medical purposes; dissolving filler, by contrast, is mostly described in international guidelines as off-label use. Off-label use is not unusual in medicine and does not in itself mean a wrong or experimental treatment: a physician may, on the basis of scientific evidence and guidelines, use a medicine outside the purposes in its licence.

What this means for you is the following: this aspect of the use and the possible risks should be explained to you clearly, your consent should be obtained and the procedure should be carried out by a physician. You can put your questions about the licensing status in Turkey and about the product to be used to your physician.

Who should perform it, and where?

Hyaluronidase is a prescription medicine, and dissolving filler is a medical procedure. Deciding whether the problem really is due to filler, assessing the type and position of the filler and intervening if an allergic reaction develops all require medical knowledge. The procedure should be carried out by a physician in a healthcare facility with emergency facilities. For the general framework, you can look at the article “Who Can Perform Medical Aesthetic Treatments? What You Need to Know as a Patient”.

Using 'filler-dissolving' products sold online, or having filler dissolved outside a healthcare facility, carries serious risk: the contents and storage conditions of the product are unknown, and there is no one to intervene if an allergy develops.

Preparing for the procedure

• Bring whatever information you have about when the filler was done, in which area and with which product, and your old photographs if you have any.
• Mention your allergies, especially any reactions to bee and wasp stings, and whether you have had a problem with this enzyme before.
• Report the medicines you take and whether you are pregnant or breastfeeding.
• Explain clearly what you want to correct: discuss whether you want all of the filler dissolved or only part of it.
• If your physician plans to carry out a skin test, allow extra time for it.

The day of the procedure, step by step

• Your medical history is reviewed, the area is examined and the part to be dissolved is determined.
• The informed consent form is read; the risk of allergy, the off-label nature of the use and the expected result are discussed, and your questions are answered.
• If the physician considers it necessary, a skin test is carried out and the result awaited.
• The area is cleaned. The enzyme is injected with a fine needle into the area where the filler lies, mostly at several points.
• The physician may massage the area gently so that the enzyme reaches the filler well.
• You are kept under observation for a while for an allergic reaction; aftercare advice is then given and a follow-up examination is planned.

After the procedure: the first 24 hours, the first week, the first month

• First 24 hours: swelling, redness, tenderness and mild itching at the injection site are common. Because the enzyme is given in fluid, the area may look fuller than it really is in the first hours.
• First 24 hours: be alert for signs of allergy; if widespread itching, hives, swelling of the face or shortness of breath develop, act according to the warnings below.
• First week: swelling and any bruising steadily lessen. During this period the area may look irregular or asymmetrical; do not judge the result early.
• First month: at the follow-up examination it is assessed whether any filler remains, and the treatment is repeated if necessary. If new filler is being considered, its timing is discussed at this stage.

For the usual course of bruising and swelling, you can refer to the article “Bruising and Swelling: How Long Do They Last after an Aesthetic Treatment, How Can They Be Reduced and When Should You Worry?”.

Expected side effects

• Swelling and redness at the injection site: usually pass within days.
• Local itching: may be a sign of a mild allergic response; if it is increasing or spreading, tell your physician.
• More volume loss than expected, or a feeling of hollowness: may be due to more of the filler being dissolved than was wanted.

Normal, consult a physician, or an emergency?

How many sessions are needed, and when is the result seen?

The enzyme’s effect begins quickly: the change is often noticed within hours to a few days. However, because swelling from the injection alters the appearance during this period, the final state of the area is usually assessed once the swelling has gone down completely.

A single treatment is enough for some people. If the amount of filler is large, if the gel is of a dense and resistant type, if a long time has passed since the filler was placed or if it was layered on several different occasions, more than one session may be needed. To avoid dissolving too much, many physicians prefer to start cautiously and repeat at follow-up if necessary. The number of sessions and the interval between them are determined by examination.

When can filler be done again after dissolving?

There is no single period that applies to everyone. Physicians generally prefer to wait for the swelling to go down, the tissue to settle and the final state of the area to be seen; in practice this period is mostly measured in weeks rather than days. New filler placed too early both makes it harder to assess the result correctly and, if active enzyme is still present in the tissue, may last a shorter time than expected.

If dissolving was carried out because of an infection, an inflamed nodule or vascular occlusion, the waiting period is longer, and whether filler should be done again is assessed separately. For the procedure itself, see the article “Hyaluronic Acid Filler: What It Is, How It Is Done and What the Risks Are”.

Realistic expectations: what can dissolving filler not do?

• It does not dissolve fillers other than hyaluronic acid.
• It is not always possible to dissolve only as much of the filler as is wanted, with millimetre precision; the result may be less or more than expected.
• It cannot be said that it will bring back exactly the appearance before the filler; in the time that has passed, the face has changed too.
• It does not remove every nodule; inflamed or infection-related nodules require other treatments.
• It is an important part of treatment in vascular occlusion, but when it is given late it cannot always prevent tissue damage.
• It is not a risk-free 'undo' button; it is the administration of a medicine with side effects of its own.

Alternatives

Which option is suitable should be decided together with your physician, who assesses the type of problem and the nature of the filler at the examination. This content is for information; it does not replace an examination.