Can granulomas develop years after filler injections?
Years after filler injections, the treated area may swell repeatedly or develop a palpable, firm lump.
When the visible volumizing effect has diminished, people may not connect these changes with their previous treatment. Rarely, however, delayed inflammatory reactions or foreign-body granulomas associated with filler may be identified years later.
In a case study of foreign-body granulomas in the oral and facial regions, patients had received filler injections approximately 3–10 years before the lesions were identified.
Although many cases involved hyaluronic acid fillers, some patients had also received other types of filler, or the precise products could not be reliably identified.
The U.S. Food and Drug Administration (FDA) also advises that some adverse effects of dermal fillers may appear weeks, months, or years after treatment.
However, it is inaccurate to call every late-developing lump at a filler injection site a granuloma.
Residual or migrated filler, noninflammatory nodules, delayed inflammatory nodules, infection, abscesses, and fibrosis can cause similar symptoms and need to be distinguished.
What is a foreign-body granuloma?
A granuloma is a chronic inflammatory tissue reaction that forms when immune cells surround material the body cannot readily eliminate.
When filler is injected, the body may recognize it as foreign material.
Most filler remains without particular problems or degrades over time. In some cases, however, immune cells such as macrophages and multinucleated giant cells gather around the filler and cause a foreign-body reaction.
Here, “nodule” is a clinical term for a lump that can be felt or seen beneath the skin. “Granuloma,” in contrast, generally refers to a specific chronic inflammatory reaction confirmed by tissue examination.
Therefore, not every delayed nodule is a foreign-body granuloma.
The following changes may occur when a foreign-body granuloma forms.
- A firm lump that can be felt at the treatment site
- Multiple small nodules beneath the skin
- Recurrent swelling at the treatment site
- Associated redness or warmth
- Pain or discomfort when pressed
- Asymmetry or an uneven surface
- A lump gradually noticed without particular discomfort
These symptoms are not specific to granulomas.
Residual filler, fibrosis, delayed inflammatory nodules, and infection can cause similar changes, so symptoms and how a lump feels alone cannot confirm a granuloma.
A granuloma may present as a single lump or occur at multiple sites along the area previously injected with filler.
Why can problems appear years later when the filler effect has faded?
Hyaluronic acid filler is an absorbable filler that generally breaks down in the body over time.
However, its duration varies with the product's characteristics, degree of cross-linking, injection volume and depth, treatment site, and individual tissue condition.
A reduction in visible volume does not necessarily mean that all filler-related material or surrounding tissue reactions have disappeared.
In addition to residual material, fibrosis or chronic inflammatory tissue around the filler may persist for a long time.
No single definitive cause explains problems arising years after filler treatment. The following possibilities are discussed.
1. A delayed foreign-body reaction associated with residual filler
Inflammation may develop later around filler that the body had tolerated without particular symptoms for a long time.
It has been suggested that hyaluronic acid filler degradation and changes in the properties of its breakdown products may affect immune responses, but the precise mechanisms of delayed inflammatory nodules have not been fully established.
2. Combined effects of filler, pathogens, and immune responses
One view is that delayed filler-related nodules may involve a combination of filler, pathogens, and the patient's immune and inflammatory responses, rather than filler material alone.
A 2023 international expert consensus suggested that filler, pathogens, and inflammation may contribute to varying degrees to many late-onset hyaluronic acid filler tissue nodules.
However, bacteria are not always identified in routine cultures, and not every late-onset nodule can be assumed to be an infection.
Conversely, a negative culture does not completely exclude infection. Clinical symptoms and test findings must be assessed together.
3. Systemic inflammation as a trigger
Sudden swelling or redness at previous filler injection sites has been reported around the time of viral or bacterial illness, infection, vaccination, or dental treatment.
The FDA also advises that inflammatory reactions such as swelling or redness around filler injection sites may occur after viral or bacterial illness, infection, vaccination, or dental treatment.
This does not mean that these events are the direct cause in every patient.
Rather, a systemic immune response may be one factor that triggers inflammation around existing filler or brings a previously asymptomatic reaction to attention.
4. Nonabsorbable fillers or unidentified injected materials
Materials that are not completely absorbed by the body, such as silicone or PMMA, may remain in the tissues for a long time.
Identifying the causative material and extent of a lesion may be more difficult when the original product is unknown or several types of filler have been injected repeatedly.
Particulate injectables that stimulate collagen production also differ from hyaluronic acid fillers in their mechanisms, persistence, and treatment. Past injected materials should therefore not all be treated as the same type of “filler.”
How many years later can this occur?
There is no fixed time limit for filler-related foreign-body granulomas that applies to every patient.
A study of 11 patients with foreign-body granulomas in the oral and facial regions found that filler had been injected approximately 3–10 years before the lesions were identified.
Most presented as painless palpable nodules. Tissue examination showed granulomatous inflammation, including foreign-body giant cells and macrophages, around spaces thought to have contained injected material.
Although many cases in this study involved hyaluronic acid fillers, some patients had also received other fillers or had a history of injections with nonabsorbable materials.
The interval of 3–10 years refers to when these patients had previously received filler, not necessarily when a granuloma first developed in each patient.
A systematic review of nodules and granulomas after lip filler reported a mean time to nodule appearance of approximately 35.2 months, or 2.9 years, after the first treatment.
However, this was not a long-term follow-up study of typical filler patients. It pooled 66 published cases in which nodules or granulomas had already developed.
Silicone was the most commonly reported material, and multiple filler types, including hyaluronic acid, were analyzed together.
The figure of 35.2 months should therefore not be interpreted as the usual time of onset or likelihood of hyaluronic acid filler granulomas.
It is not possible to conclude that a problem is unrelated to previous filler simply because several years have passed. A new lump or recurrent swelling at a previously treated site warrants reviewing even remote treatment history.
Are all lumps that appear late granulomas?
No. This is the most important distinction in diagnosis.
Lumps felt at a filler injection site long after treatment may have the following causes.
Residual or migrated filler
Filler may collect in one area or migrate from its original injection site, creating a bulge. It may feel like a lump even without inflammation or granuloma formation.
Noninflammatory nodules
A nodule may be palpable without redness or pain if excessive filler was injected into one area or distributed unevenly within the tissue.
Delayed inflammatory nodules
Nodules with swelling, redness, warmth, or tenderness may develop well after treatment. Possible infection must be assessed alongside filler-related immune and inflammatory reactions.
Infection or abscess
Pain, warmth, marked redness, pus, drainage, or skin damage require assessment for infection or an abscess.
Routinely using hyaluronidase or steroids alone without adequately assessing possible infection may be inappropriate.
Fibrosis and capsules
After repeated filler injections or inflammation, surrounding tissue may harden and feel like a lump or a plaque. Fibrotic tissue may then contribute more to the symptoms and texture than the filler itself.
Foreign-body granuloma
This is a chronic foreign-body reaction surrounding filler material. Clinical symptoms alone may not establish the diagnosis; when necessary, tissue examination is used to confirm granulomatous inflammation.
Unrelated epidermal cysts, lipomas, lymph node or salivary gland disorders, and other soft-tissue masses may also feel similar. A history of filler treatment does not mean every lump is a filler complication.
How are filler granulomas diagnosed?
Diagnosis begins with a detailed treatment history and a review of how the current symptoms have developed.
The following information should be checked as far as possible.
- When filler was injected
- Injection sites and number of treatments
- Product names and ingredients
- Whether the material was hyaluronic acid filler or a nonabsorbable substance
- Whether different filler types were injected into the same area
- Any previous filler dissolution or removal treatment
- When symptoms first began and how they have changed
- Any recent infection, vaccination, dental treatment, or other procedures
- Associated pain, redness, warmth, pus, or drainage
Even if you cannot remember the product name, providing the clinic, approximate dates, injection sites, and number of treatments can help with diagnosis.
In-person examination
The clinician assesses the lump's location, size, depth, firmness, mobility, tenderness, and overlying skin changes, as well as whether its location corresponds to the area previously injected.
Firmness or the presence or absence of pain alone cannot establish whether a lump is a granuloma.
Imaging
When needed, high-frequency ultrasound or other imaging may help assess the location, depth, and distribution of suspected filler, surrounding tissue, and any inflammation or fluid collection.
If a lesion is too deep or widespread for ultrasound to assess its full extent, additional imaging such as MRI may be used.
However, imaging alone cannot confirm every foreign-body granuloma. Findings vary with filler type, injection layer, and tissue changes and must be interpreted alongside treatment history and examination findings.
Is dissolving hyaluronic acid filler enough?
Not every filler-related lump resolves with hyaluronidase.
Hyaluronidase is an enzyme that breaks down hyaluronic acid. It may be used when the causative material is hyaluronic acid and residual filler is an important contributor to the lesion.
However, hyaluronidase alone may not adequately resolve the following situations.
- Injection of a material other than hyaluronic acid
- Fibrotic tissue contributing more than the filler itself
- Established granulomatous inflammatory tissue
- Associated infection or abscess
- A mixture of different filler types
- Filler or foreign material spread widely or deeply
- Distortion of surrounding tissue from recurrent inflammation
Hyaluronidase can break down hyaluronic acid filler, but it does not directly remove established fibrotic tissue or all granulomatous inflammatory tissue.
In particular, infectious nodules and noninfectious inflammatory nodules may require different approaches. Starting steroids without adequately assessing infection may worsen an infection. Conversely, repeatedly using antibiotics alone on the assumption that every delayed nodule is infectious may also be inappropriate.
Treatment is therefore not simply a decision about whether to dissolve filler. The causative material, infection and inflammation, degree of fibrosis, and lesion depth and extent must be considered together.
How are filler granulomas treated?
No single treatment for delayed filler-related nodules applies to every patient. Treatment choice and sequence depend on the causative material, inflammatory activity, likelihood of infection, presence of an abscess, and lesion extent.
Depending on the condition, the following approaches may be considered.
- Observation of asymptomatic or stable lesions
- Hyaluronidase for residual hyaluronic acid filler
- Appropriate antibiotics when infection is suspected
- Anti-inflammatory treatment or intralesional injections after assessing possible infection
- Drainage of an abscess
- Surgical removal of lesions persisting despite repeated treatment
- Biopsy when the cause is unknown or distinction from other masses is needed
The FDA also explains that filler-related nodules or granulomas may require injections, oral antibiotics, or surgical removal, depending on the condition. This does not mean every patient receives all three treatments in the same order; treatment varies with the lesion's cause and condition.
Foreign material that is extensively mixed with surrounding tissue or spread across multiple layers may be difficult to separate completely from normal tissue. Attempting to remove all of it aggressively may cause skin depressions, scars, injury to nerves or surrounding structures, or asymmetry.
Even surgical removal cannot guarantee removal of all finely dispersed foreign material. The extent of removal and treatment goals should account for the lesion's location and depth, surrounding tissue condition, and potential damage to normal tissue.
These symptoms require prompt medical attention
If the following changes occur, seek medical care rather than waiting on the assumption that the problem is purely cosmetic.
- A rapidly enlarging lump
- Increasing pain or warmth
- Redness or a change in skin color
- Pus or drainage
- Thinning or breakdown of the skin
- Recurrent swelling or swelling lasting longer
- Sudden, severe swelling on one side of the face
- Systemic symptoms such as fever
- Visual disturbance or severe pain with a lesion around the eye
In particular, changes in vision, skin turning white, gray, or blue, or sudden neurological abnormalities require immediate medical assessment.
Rather than assuming a granuloma simply because the site was previously injected, it is important to distinguish infection, abscesses, and other masses unrelated to filler.
Frequently asked questions
Q. Can hyaluronic acid filler remain for 5 years or longer?
A. Persistence varies with the product, injection site and volume, cross-linking characteristics, and individual tissue condition. Loss of visible volume does not establish that all filler-related residue or surrounding tissue reactions have disappeared. However, a lump found 5 or more years after treatment is not necessarily residual hyaluronic acid filler. Examination and appropriate tests may be used to distinguish residual filler, fibrosis, inflammatory nodules, and other masses.
Q. Could a granuloma still be related to filler injected 10 years ago?
A. The possibility cannot be completely excluded. A case study of foreign-body granulomas in the oral and facial regions reported filler injections approximately 3–10 years before the lesions were identified.
However, the study also included non-hyaluronic acid fillers and mixed treatments. It does not mean that every new lump 10 years after treatment is a filler granuloma. Other soft-tissue masses need to be considered.
Q. Does a granuloma feel hard?
A. It can feel firm, but texture alone cannot confirm a granuloma. Residual filler, fibrosis, infectious nodules, and other masses may also feel firm.
Q. Can a filler granuloma be painless?
A. Yes. Active inflammation may cause pain, redness, and swelling, but sometimes a lump is palpable without pain. Painless palpable nodules were also commonly reported in the case study of oral and facial foreign-body granulomas.
Q. Will a granuloma disappear immediately if the filler is dissolved?
A. Hyaluronidase may help if the material is hyaluronic acid and residual filler is an important contributor.
However, hyaluronidase is an enzyme that breaks down hyaluronic acid; it does not directly eliminate infection, fibrosis, or all established granulomatous inflammatory tissue. Multiple sessions or other treatments may be needed depending on the lesion.
Q. Can the problem be diagnosed if I do not know which filler I received?
A. Even without the product name, the timing, sites, and number of treatments, symptom changes, in-person examination, and imaging can help narrow the cause.
Diagnosis and treatment may be more complex after repeated injections of different filler types. Biopsy may be considered when the cause is unclear or other conditions need to be distinguished.
Previous filler treatment should be reviewed even years later
Delayed inflammatory nodules and foreign-body granulomas associated with filler are uncommon, but they may appear months to years after treatment. A firm lump, recurrent swelling, redness, or pain at a previously injected site warrants assessing a possible link, even if the treatment was long ago.
However, not every late-developing lump is a foreign-body granuloma. Residual filler, filler migration, noninflammatory nodules, infection and abscesses, fibrosis, and unrelated soft-tissue masses may present similarly.
Before dissolving filler or giving anti-inflammatory injections based on symptoms alone, treatment should follow identification of the cause through treatment history, in-person examination, and, when needed, imaging, cultures, or biopsy.
If you are concerned about facial foreign material or filler granulomas, contact us at 02-545-3700 or through “UVOM Plastic Surgery” on KakaoTalk.
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