top of page

Dermal Fillers: 7 Adverse Events & Treatments

The rapid surge in popularity of dermal fillers in recent years stems from their ability to deliver rejuvenating and enhancing aesthetic improvements that were previously only achievable through surgery. Notably, these benefits come at a lower cost and entail minimal to no recovery time.

Dermal fillers primarily find application in addressing wrinkles, folds, and the restoration of lost soft tissue due to age or disease. Their utility, however, is increasingly seen in volume replacement and enhancement procedures. These encompass a spectrum of treatments, such as cheek and chin augmentation, tear trough correction, nose reshaping, midfacial volumization, lip enhancement, hand rejuvenation, and rectification of facial asymmetry. With the rise in both the scope of applications and the number of procedures undertaken, a corresponding increase in complications is expected.

Effectively managing these complications necessitates a comprehensive understanding of various factors, including the characteristics, capabilities, injection techniques, risks, and limitations associated with the diverse range of available fillers. Such expertise is vital for injectors to mitigate risks, enhance patient outcomes, and provide care to individuals encountering adverse events. This expertise must extend even to products that may not be available in the injector's country of practice, as patients could present adverse reactions from fillers administered abroad. Particularly pertinent is the assessment of whether local adverse events post-treatment arise from the injection technique itself or the chemical composition of the dermal filler.

In this blog, the underlying causes of filler-related complications and guidance on both prevention and treatment strategies, will be discussed.

Categories of Dermal Fillers

Various methods of categorizing dermal fillers are available, but it is particularly helpful to classify them based on whether they are biodegradable or nonbiodegradable, when discussing complications related to these fillers

1. Biodegradable Fillers

Biodegradable fillers with a moderate duration, like collagen and hyaluronic acid (HA) fillers, are absorbed by the body relatively quickly, resulting in shorter-lasting cosmetic effects. Among these, HA derivatives are extensively utilized biodegradable fillers, offering effects that typically endure for 6 to 18 months, contingent on factors such as source, degree of cross-linking, concentration, and particle size.

Hyaluronic acids are composed of linear polymeric dimers of N-acetyl glucosamine and glucuronic acid, with variations arising from proprietary cross-linking methods, chain cross-linking extent, particle size uniformity, and concentration. These attributes significantly influence their clinical impact. Augmenting cross-linking and concentration enhances viscosity, elasticity, and resistance to degradation by natural hyaluronidase. Due to HA's hydrophilic nature, more concentrated or larger particle products tend to absorb more water, leading to greater tissue swelling post-injection. HA products are also characterized by the size of their microspheres. Different HAs exhibit varying levels of hardness (G'), affecting their suitability for specific procedures. Generally, products with higher G' values should be injected deeper. However, it's important to note that while more concentrated and cross-linked products have prolonged effects, they also elevate reactivity in the body, increasing the risk of inflammation and granuloma formation.

2. Nonbiodegradable Fillers

Nonbiodegradable fillers trigger a foreign body reaction, prompting fibroblastic collagen deposition around the nonabsorbable microspheres. The permanent nature of nonbiodegradable fillers can result in enduring and challenging-to-treat complications.

Dermal Filler Complications

Every type of filler carries a potential for both short-term and prolonged complications. As the range of applications broadens and the frequency of treatments rises, the variety and occurrence of unfavorable incidents also grow. Although the majority of adverse reactions tend to be mild and fleeting, there is a possibility of more severe complications that can lead to enduring or even permanent functional and aesthetic impairments. Certain reactions manifest immediately following the procedure, while others might have a delayed onset.

1. Bruising

All dermal fillers carry the potential to induce bruising, with increased occurrence when injected into the dermal and immediate subdermal layers using techniques like fanning and threading. However, employing the depot technique at the preperiosteal level generally leads to less bruising. Bruises can be managed by applying cold compresses and using vitamin K cream. For stubborn discoloration, treatment with pulsed dye light or potassium titanyl phosphate lasers can be effective due to their precise absorption by hemoglobin.

To minimize bruising, steps include discontinuing blood-thinning medications a week before the procedure, avoiding sun exposure during bruising, and refraining from intense exercise for the initial 24 hours to prevent heightened blood pressure. Fillers containing lidocaine and epinephrine may decrease post-injection bruising, enhancing injection comfort and inhibiting eosinophil activation responsible for bruising and promoting vasoconstriction during the procedure. Keeping the patient's head elevated throughout and for 24 hours after the procedure helps limit bruising. Using the smallest gauge needle, slow injection with small product amounts, employing blunt cannulas, and reducing the number of puncture sites can further minimize bruising.

See below the figure for a case of bruising after the use of dermal fillers. (Taken from Funt et al, 2015)

Bruising, dermal fillers

2. Edema

Short-term Post-Traumatic Edema

Transient swelling immediately after a dermal filler procedure is a typical occurrence and is associated with all types of fillers. This swelling emerges shortly after injection and is influenced by factors like injection volume and technique. Similar approaches used for managing and preventing bruising are applicable to this kind of edema. In most instances, edema resulting from post-injection trauma tends to resolve within one week.

Antibody-Mediated Edema (Angioedema)

Dermal fillers can trigger a hypersensitive reaction in certain individuals, characterized by an immune response mediated by immunoglobulin E (IgE), known as a Type I hypersensitivity reaction. This can happen after the first or subsequent exposures. IgE prompts mast cells to release various substances like histamine and cytokines, causing symptoms like swelling, redness, pain, and itching associated with allergic responses. Angioedema, marked by swelling beneath the skin's surface, can manifest within hours of exposure, and severe reactions may persist for weeks.

Managing angioedema, whether due to a known allergen or of unknown origin, hinges on its severity. Often, swelling subsides naturally over a few hours or days. When mast-cell mediated, antihistamines effectively address short-lived swelling. For persistent or non-responsive cases, oral prednisone is the main treatment, with careful monitoring to rule out infection. Swiftly progressing angioedema necessitates immediate attention due to potential airway obstruction risks.

Chronic angioedema, lasting over 6 weeks, is challenging to manage and exhibits variable medication responses. Treatment escalation, involves step-wise approaches, with each added to the previous if the response is inadequate. Effective edema control with the least oral steroid dose is the goal. Combining a leukotriene receptor antagonist like montelukast with steroids has shown success in reducing steroid doses while binding specifically to cysteinyl leukotriene sites.

Nonantibody-Mediated (Delayed) Edema

Delayed hypersensitivity reactions exhibit characteristics like induration, erythema, and edema, and are mediated by T lymphocytes instead of antibodies. These reactions typically manifest a day after injection, but their onset can be delayed by several weeks, persisting for months. They do not respond to antihistamines. Addressing the allergen involves its removal. Treating delayed hypersensitivity reactions from hyaluronic acid (HA) may require hyaluronidase, while other fillers might necessitate steroids until the filler dissipates, along with potential laser treatment or extrusion. As a last resort, excision could be considered. Managing symptoms involves using the minimum effective dose of oral steroids (prednisone).

Malar Edema

Malar edema, a serious complication associated with all types of fillers, can occur when injected into the infraorbital hollow and tear troughs. In a study of 51 patients, the placement of HA gel in the infraorbital hollows led to prolonged periorbital edema lasting around 5.4 months. The infraorbital hollow, bounded by the medial and lateral canthus and the orbicularis oculi's lower border, is prone to such issues due to the malar septum dividing the superficial suborbicularis oculi fat into compartments with differing lymphatic drainage. Edema can result from fluid accumulation and pressure on lymphatics due to improper injection technique or filler properties. Patient factors also play a role.

Addressing malar edema involves elevation of the head, cold compresses, manual compression, and methylprednisolone. Hyaluronidase is recommended for HA-treated patients. To prevent malar edema, careful filler selection, limiting volume, and placing filler deep to the malar septum are suggested. An HA filler with low elasticity and viscosity is preferable, and superficial injection with appropriate materials in small quantities can also be considered. Distinguishing persistent malar edema from overcorrection is crucial.

See below the figure for a case of acute generalised facial edema. (Taken from Funt et al, 2015)

Facial edema, dermal fillers

3. Skin Discolouration


Immediate skin redness following injection is considered normal. However, if the redness persists beyond a few days, it might indicate a hypersensitivity reaction. Treating it could involve methods effective for rosacea, such as oral tetracycline or isotretinoin. For continuous redness, a medium-strength topical steroid is recommended, though caution is advised to avoid prolonged use of high-potency steroids, which can lead to atrophy and telangiectasias. Lasers can be beneficial for treating telangiectasias and erythema, and vitamin K cream can aid in resolving erythema and facial bruising. It's important to note that individuals with rosacea are at a heightened risk of post-injection erythema, and this potential risk should be communicated before initiating the procedure.

See below the figure for a case of erythema at the site of injection. (Taken from Funt et al, 2015)

Erythema, dermal fillers


Following dermal filler injection, new capillaries, arterioles, and venules might emerge at the injection site. These minute vessels could become visible days or weeks after the procedure, gradually fading away within 3 to 12 months without additional intervention. These vascular developments are attributed to tissue trauma resulting from product-induced tissue expansion and/or excessive manipulation like molding and massaging. Effective lasers for treating these small vessels include the 532-nm KTP, the 532-nm diode copper vapor, the 585-nm pulsed dye lasers, and intense pulsed light (IPL). The choice of laser depends on vessel size. Further information on laser treatment is available in the Bruising section.


According to ASAPS 2011 data, around 21% of cosmetic procedures were performed on racial and ethnic minorities. Patients with darker skin tones, tend to experience post-inflammatory hyperpigmentation following dermal filler procedures due to their skin's propensity for hyperpigmentation after trauma. Although post-injection hyperpigmentation can occur in other skin types as well, it's more common in these individuals.

To address persistent hyperpigmentation resulting from dermal filler injections, the initial treatment involves using a bleaching agent like topical hydroquinone (2%–8%) and Retin-A (tretinoin) alongside daily application of broad-spectrum sunscreen. Chemical peels can be considered for resistant cases. If these measures prove ineffective, subsequent steps include treatment with IPL, pulsed dye laser, fractional laser, or the low fluence Q-switched Nd:YAG 1,064 nm laser. While many lasers have limitations in treating Fitzpatrick skin types IV–VI, the Nd:YAG laser with its long wavelength can effectively treat darker skin without disturbing its natural color, and IPL systems are suitable for Fitzpatrick skin types I–IV.

Reducing post-injection erythema, and consequently post-inflammatory hyperpigmentation, can be achieved by minimizing the number of skin punctures during injections. Techniques like linear threading, fanning, or injecting at the preperiosteal level can help in this regard.


Improper implantation of particulate HA fillers into the superficial dermis or epidermis can lead to a bluish tint, known as the Tyndall effect, where light scattering by suspended particles causes a blue hue due to the higher frequency of blue light waves. The intensity and duration of discoloration depend on how superficially the material is placed.

Hyaluronidase is the recommended initial treatment. For HAs with high cross-linking or large particle size that are less responsive to hyaluronidase, multiple treatments might be required. If needed, a final option involves addressing dyspigmentation by gently nicking the skin with a small-gauge needle (30 gauge) or surgical scalpel to remove the superficial unwanted filler. This procedure can be performed shortly after injection or up to 12 months later.

4. Infection

Like any procedure involving skin penetration, dermal filler injections carry an infection risk. To minimize this risk, employ an effective topical disinfectant to sterilize the injection site, handle sterilized needles and syringes from their individual packaging, wear gloves throughout the process, and ensure the needle remains uncontaminated. Avoid wiping excessive filler material off the needle tip with nonsterile gauze; instead, flick off any remaining material.

While uncommon, persistent infections after filler injections can occur and might be caused by bacteria, fungi, or viruses. Additionally, there is a possibility of virulent late infections known as biofilms.

Erysipelas and Phlegmon

Erysipelas and phlegmon are infections that cause widespread inflammation in the skin or connective tissue. Typically, Staphylococcus aureus or Streptococcus pyogenes bacteria are responsible, though an unusual infection might be indicated if a new lesion emerges more than two weeks after a procedure. Distinguishing these infections from delayed hypersensitivity reactions is important; while both lead to redness, hypersensitivity reactions usually involve itching and lack fever.

If left untreated, these conditions can progress to sepsis, particularly in the elderly or those with diabetes or compromised immune systems. Mild cases may be managed with oral antibiotics, while severe instances require hospitalization and intravenous antibiotics effective against S. aureus, such as cephalexin, dicloxacillin, or nafcillin. Avoid massaging the area to prevent infection spread.


The occurrence of abscess formation is infrequent but can arise within a span of 1 week to several years post-treatment. These abscesses might persist for weeks, even recurring intermittently for months. Management involves incision, drainage, and antibiotics, with the collection of cultures for sensitivity testing. Tailoring treatment based on sensitivity reports is crucial. In rare instances, infections in the midfacial and periorbital regions could potentially lead to intracerebral complications.

Herpetic Outbreak

Injecting dermal fillers can trigger the reactivation of herpes virus infections, particularly when targeting the lips or mouth area. If a person has a history of cold sores, it is advisable to initiate preventive treatment with valaciclovir (500 mg twice daily) for 3-5 days before the injection to lower the risk of this happening. In case prophylactic treatment wasn't administered and an infection is detected early, a dose of 2 g of valaciclovir twice daily for 1 day is recommended. If a secondary infection occurs, appropriate antibiotics should be prescribed.

Herpetic recurrences commonly appear around the perioral area, nasal mucosa, and the mucosa of the hard palate. Although extremely rare, shingles can occur after injection. If a blistering reaction arises outside the regions typically affected by recurrent herpes simplex virus infections (such as the skin of the lips and vermillion, nasal mucosa, and mucosa of the hard palate), vascular compromise should be considered as a potential cause.

5. Nodular Masses

Nodules often appear following soft tissue augmentation and may have various underlying causes, necessitating thorough investigation for accurate diagnosis. These nodules are more noticeable in regions with thinner skin. It is important to differentiate between inflammatory and noninflammatory nodules.

Noninflammatory Nodules

When an excessive amount of filler accumulates due to poor technique (overcorrection, superficial placement, or improper use), it can lead to the formation of palpable and sometimes visible noninflammatory nodules. These nodules are distinct lumps in the injection area, appearing soon after the procedure. It's important to differentiate them from inflammatory nodules, foreign body granulomas, or biofilms which manifest later and involve inflammation.

Problematic filler placement and the use of particulate fillers in mobile regions like the lips can cause delayed-onset noninflammatory nodules. Resolving nodules from HA fillers can be achieved through hyaluronidase treatment. Early nodules from non-HA fillers might respond to vigorous massage or extrusion. Persistent nodules may be addressed through various methods, including intralesional steroids, injections of 5-fluorouracil (5-FU), triamcinolone, and lidocaine, or fractional lasers after the carrier gel has been absorbed.

Implant nodules are a common adverse outcome following dermal filler procedures, and their occurrence can be minimized by ensuring proper filler placement, selection, and massage techniques during injection. Intramuscular injection should be avoided. In extreme cases, if nodules remain unresponsive and become increasingly fibrotic, excision might be considered.

See below the figure for a case of noninflammatory nodules. (Taken from Funt et al, 2015)

Non inflammatory nodules, dermal fillers

Inflammatory Nodules: Biofilms

Biofilms, common in nature, consist of densely packed bacterial communities enveloped in secreted polymers. When materials are injected into the skin, they can become coated with bacteria, forming biofilms. These bacterial collections generate a protective matrix, leading to chronic infections resistant to antibiotics. Mature biofilms release individual bacteria, causing various infections upon activation. Distinguishing biofilm-related inflammation from hypersensitivity is challenging, emphasizing prevention. Suspicion arises with persistent redness or swelling post-treatment.

Diagnosis and treatment of biofilm-related issues are intricate. Antibiotics like ciprofloxacin and clarithromycin are initial options, followed by hyaluronidase or laser technology. Biofilms are rare, but precautions are crucial during filler injections.

6. Paresthesia

Inadvertent nerve damage is a rare but serious complication of dermal filler procedures. It can arise from direct trauma to the nerve during injection, filler compression on the nerve, or excessive manipulation. Nerve injury might be temporary or permanent, with various types of damage. Neurapraxia, where the nerve is injured without axonal disruption, may cause sensory or motor issues, usually improving in 2-3 weeks. Transection of small cutaneous sensory nerves might lead to temporary numbness. Complete nerve transection can result in permanent damage, most commonly observed in the infraorbital nerve.

Treatment involves triamcinolone, lidocaine, and sometimes neurotrophic supplements. Comprehensive knowledge of facial anatomy is vital to avoid danger zones and anticipate nerve structures. Deep injections with contact to bone rarely lead to intraneural injections, but overzealous massage can push material into nerve foramina.

7. Vascular Compromise Vascular compromise is a significant and immediate complication that can occur following filler injection. It usually happens when the filler is inadvertently injected into an artery, causing an embolism that disrupts blood flow. Injectors must have a strong grasp of facial anatomy to prevent this issue. Rapid identification of a vascular event and prompt, aggressive intervention are crucial to prevent severe and potentially irreversible consequences. Injecting filler into an artery can lead to tissue necrosis both forward and backward along the blood flow. There have been instances of acute vision loss and hemiplegia following autologous facial fat injection due to embolisms in ocular and cerebral arteries. In some cases, like injecting fat into the glabella, it has even led to fatal stroke. It is believed that fragments of injected fatty tissue traveled through reverse flow immediately after injection, causing the embolism.

Retinal Artery Occlusion

Retinal artery occlusion is a rare occurrence that can happen when dermal filler enters the eye's blood circulation due to unintended injection into certain branches of the ophthalmic artery. These branches include the angular artery, zygomaticotemporal artery, zygomaticofacial artery, and dorsal nasal artery, as well as the supratrochlear and supraorbital arteries. When filler is injected into these arteries with pressure exceeding the arterial pressure, the material can travel towards the central retinal artery's origin. Upon pressure release, the material can move into the retinal artery, blocking blood supply to the retina and potentially causing sudden vision loss or even blindness. If any visual issues arise after facial filler injection, immediate consultation with an ophthalmologist is crucial.

To reduce the risk, injections in these areas should be directly on bone, and if the needle encounters any obstruction, it should be repositioned at the preperiosteal level, where there are no vessels.

Tissue Necrosis

Unintentional injection of filler into blood vessels supplying the skin or mucosa can lead to tissue death due to vessel blockage. The filler may flow forward, backward, or both within the vessel during injection. After injection stops, the filler can travel through the blood vessels, causing local or distant tissue death. This can also occur due to swelling or blockage of nearby vessels caused by the filler's properties. Necrosis risk is higher with particulate fillers, especially in areas heavily reliant on a single blood supply branch, like the glabellar and nasolabial folds. Immediate action is vital if signs of impending necrosis, such as unusual pain and blanching, appear.

Treatment includes stopping injection, applying hyaluronidase and nitroglycerin paste, using warm compresses, administering medications like methylprednisolone and Lovenox, and considering hyperbaric oxygen therapy in severe cases. Prophylactic antibiotics and antivirals should be given. Factors increasing vessel blockage risk include large injections, small needles, stationary needles, high pressure, and deep injection planes. Necrotic areas can also be vulnerable to secondary infections.

See below the figure for a case of tissue necrosis. (Taken from Funt et al, 2015)

Tissue necrosis, dermal fillers


Over the past ten years, numerous new soft tissue fillers have emerged for facial rejuvenation. These fillers not only diminish wrinkles but also restore facial volume for a more balanced and natural rejuvenated appearance. To achieve satisfying cosmetic outcomes, practitioners of facial rejuvenation must thoroughly comprehend the unique attributes of available fillers, including their uses, limitations, benefits, drawbacks, and strategies for preventing complications.


Evaluating hyaluronic acid dermal fillers: A critique of current characterization methods (2022)

Dermal Fillers in Aesthetics: An Overview of Adverse Events and Treatment Approaches (2015)

Dermal fillers: an update (2015)

Dermal fillers: facts and controversies (2013)


Master the Injection Techniques of Lip Augmentation & Eye Rejuvenation with Combination Therapies in our upcoming Hands-on Mini Fellowship happening globally:

IFAAS Mini Fellowship (Hands-On)

Korean Non-surgical Aesthetic Injections:

Lip Augmentation, Eye Rejuvenation & Facial Contouring

Tailored Aesthetic Injections, Toxins, HA Fillers, Skin Boosters

Oct 23-24, 2023 - Seoul, South Korea - [Register Now]


More Upcoming Aesthetic Trainings Happening Globally


bottom of page