Nearly all species, from bacteria to mammals, have hyaluronic acid in their bodies. The polysaccharide is present in eyes, joints, and skin, providing hydration, lubrication, and support. Because the substance is so common, dermatologists welcomed it as a safer alternative to collagen for filling wrinkles. Despite this, there may still be a small risk, of 0.6 to 0.8 percent, that a patient will experience a hypersensitivity reaction to a hyaluronic acid dermal filler injection. Although rare, it is important to minimize the risk of a hypersensitivity reaction after a wrinkle injection.

Possible Hypersensitivity Reactions to Hyaluronic Acid

An injection of hyaluronic acid into soft tissue can trigger either an immediate or a delayed hypersensitivity reaction, up to a few weeks after treatment. Most of these reported hypersensitivity reactions resolve with or without treatment within a week or two, and the reactions are usually mild to moderate if they do occur, rarely severe. These reactions can include:

  • Swelling
  • Itching
  • Shortness of breath
  • Nodules

With these reactions having the potential for scarring in severe cases.

Cause of Hypersensitivity Reactions

Dermal fillers usually trigger hypersensitivity reactions when they contain bacterial proteins mixed in with the hyaluronic acid. Most modern hyaluronic acid dermal fillers are made from bacterial fermentation, although some similar products for orthopedic injections get their hyaluronic acid from rooster combs. Because the dermal fillers are produced by bacteria, there is a chance the end product will contain endotoxins from the bacteria. These endotoxins are molecules found in the cell wall of Gram-negative bacteria, and although these bacteria may not be pathogens, the endotoxins can produce an immune response in animals. As the body fights this foreign invader, the injected area can swell and nodules may form to cordon off this perceived threat. Although these hypersensitivity reactions are rare, the chance is there, making it a risk doctors and patients have to consider when choosing dermal filler treatments.

Treatment of Hypersensitivity Reactions

Most hypersensitivity reactions, if they occur at all, should be mild to moderate. However, if the reaction is concerning, treatments may include:

  • Antihistamines to calm the body’s allergic reaction
  • Corticosteroids to reduce immune response
  • Skin creams to soothe the area
  • Ice packs to reduce swelling
  • Hyaluronidase to break down hyaluronic acid
  • Surgery to remove nodules

For mild swelling, applying ice and taking antihistamines may do the trick, but it is important to monitor the recipient for a more severe allergic reaction.

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How to Prevent Hypersensitivity Reactions

Although rare already, there are steps you can take to reduce the chance of a hypersensitivity reaction. These can include:

  1. Patient selection: Most dermal filler manufacturers suggest avoiding use of the fillers in certain individuals. These can include clients with an autoimmune disease or an otherwise compromised immune system, who may be more susceptible to these bacterial proteins triggering a reaction.
  2. Location, location, location: Some have suggested areas like the lips can be more sensitive, and more susceptible to a hypersensitivity reaction, although this is a common injection location. Swelling is more likely to occur in the lip area than other areas of the face. As well, areas with an existing skin disease or an open wound may be more sensitive, and manufacturers usually recommend avoiding using fillers in these areas of broken skin because of the potential risk.
  3. Skin test: Most manufacturers suggest a skin test is not required for hyaluronic acid filler injections, unlike the collagen injections of the past. That said, some dermatologists prefer to perform a skin test anyway, especially if they suspect their patient may be more likely to have a hypersensitivity reaction.
  4. Choice of dermal filler: One of the earliest approved hyaluronic acid fillers was RESTYLANE®, which was associated with some rare hypersensitivity reactions. Purification techniques have improved over the years, with modern dermal fillers less likely to contain bacterial proteins which can trigger a hypersensitivity reaction. Some brands, such as TEOSYAL®, put extra effort into purifying their hyaluronic acid gels with their special patented technology. This highly-pure hyaluronic acid has a reduced protein and bacterial endotoxin level, making it less likely to trigger a hypersensitivity reaction. The manufacturers claim the filler is non-allergenic and will not require a skin test before treatment. TEOSYAL® fillers can provide results lasting up to eighteen months, and the wide range of fillers treat everything from dehydrated skin to fine lines to deep wrinkles and lost volume. Some TEOSYAL® products are designed to integrate so well into tissue they will adapt easily to facial movement for a more natural look, and some have extra ingredients such as amino acids to help restructure skin. There are almost twenty different TEOSYAL® products to choose from, all produced to have a highly-pure formula.

Although hypersensitivity reactions from hyaluronic acid fillers, like Ellanse are rare, they are a risk that practitioners and patients need to be aware of. Using a highly purified dermal filler, such as TEOSYAL®, may help minimize this risk. To learn more about the different TEOSYAL® products or to purchase Ellanse and other dermal fillers for your Medical Spa, visit