Filler granuloma and delayed-onset nodules: lumps that appear months or years later

What is a filler granuloma?

A filler granuloma is a firm lump that forms when immune cells gather around dermal filler and wall it off because the body treats the material as foreign. Doctors call it a foreign body granuloma. Under the microscope it is made of immune cells called macrophages, some of which fuse into giant cells when they cannot clear the material (Lee and Kim, 2015).

• It is an immune reaction, not an allergy in the usual sense, and it is different from an infection, although infection can look similar and may act as a trigger.
• It appears late: typically months to years after injection, often after a long period with no problem at all.
• It can affect several sites: lumps may appear at more than one injection site at about the same time, and can be larger than the amount of filler placed.
• It is rare: most people who have filler never develop one.

The word is often used loosely for any late lump. Strictly, a granuloma is a diagnosis made from a tissue sample, so doctors prefer the wider term delayed-onset nodule until the cause is known (King and colleagues, 2016). For how SkinRev Lab approaches filler problems in general, see filler correction at SkinRev Lab.

Granuloma, delayed-onset nodule or ordinary lump: what is the difference?

A delayed-onset nodule is any lump that appears at or near a filler site weeks to years after treatment, and a granuloma is one specific, uncommon cause of it. Doctors sort filler lumps by when they appear and whether they are inflamed, because each group is managed differently (King and colleagues, 2016; Funt and Pavicic, 2013).

Ordinary lumps and their causes are covered in our guide to filler lumps and nodules; this page concentrates on the last two rows.

How common are filler granulomas and delayed-onset nodules?

Filler granulomas are rare and delayed-onset nodules are uncommon; published estimates vary with the product and with how each study defined a lump.

• True foreign body granulomas, all fillers: estimated at 0.01 to 1 per cent of treated people, which is between about 1 in 10,000 and 1 in 100 (King and colleagues, 2016; Funt and Pavicic, 2013).
• Hyaluronic acid filler: one review quotes 0.02 to 0.4 per cent for granulomas (Lee and Kim, 2015).
• Hypersensitivity reactions to hyaluronic acid filler, including nodules: 0.6 to 0.8 per cent in a four-year retrospective study cited in UK guidance (King and colleagues, 2016).
• Older and particulate materials: rates have been higher with some earlier products, and improved formulations have lowered them (Lee and Kim, 2015).

Why the ranges are wide:

• Many lumps are never sampled, so some reported "granulomas" may be other kinds of nodule.
• Reactions can appear years later, after people have lost touch with the doctor who treated them.
• Products, amounts and techniques differ between studies.

These are figures from published studies and cannot give an exact risk for one person. The practical point is that a late lump after filler is far more often an ordinary nodule or a passing inflammatory reaction than a true granuloma.

Why do lumps appear months or years after filler?

Lumps appear months or years after filler because the immune system can begin reacting to material it had previously tolerated, sometimes after a trigger such as an infection elsewhere in the body. Researchers describe several overlapping explanations, and doctors cannot yet predict who will be affected (Lee and Kim, 2015; King and colleagues, 2016).

• Foreign body reaction: immune cells that cannot clear the filler surround it instead, forming a granuloma.
• Low-grade infection or biofilm: bacteria introduced at injection may lie dormant on the filler and reactivate later. Reviews note that this is debated and is hard to tell apart from an immune reaction.
• Delayed immune sensitivity: people with active autoimmune or allergic conditions appear to be at higher risk.
• A triggering event: reported triggers include a bacterial infection elsewhere in the body, a period of illness, injury to the area and a further filler session over old product.

Factors linked with higher risk:

• Larger volumes of filler, and repeated top-ups in the same place.
• Injection into muscle or too close to the surface.
• Particulate fillers; the surface and purity of the particles affect how the body reacts.
• Mobile, thin-skinned areas such as the lips and around the eyes.

A lump is different from filler that has moved or built up; see filler migration and filler fatigue for those.

Which fillers are linked with granulomas?

Granulomas have been reported after every type of injectable filler, but they look and behave differently depending on the material, and long-lasting and particulate fillers account for a larger share (Lee and Kim, 2015).

• Hyaluronic acid: uncommon. The reaction is usually cystic, meaning soft and fluid-filled, and can resemble an abscess. The filler itself can be dissolved.
• Collagen fillers: also usually cystic. DermNet notes that granulomas from an older bovine collagen filler often regress within one to two years.
• Poly-L-lactic acid: firm, sclerosing (hard, scar-like) granulomas have been described. See our guide to poly-L-lactic acid collagen stimulators.
• Calcium hydroxylapatite: typically causes nodules from product placement more than true granulomas. See calcium hydroxylapatite filler.
• Silicone, paraffin and acrylic or polyacrylamide materials: non-absorbable fillers. Reactions can appear very late, with silicone reactions reported 10 to 15 years after injection, and can persist.

Why the material matters: only hyaluronic acid responds to the dissolving enzyme, so the options for other fillers are narrower. Many people have had more than one product in the same area over the years and do not know what was used, which is where imaging helps. For collagen products and collagen stimulators, see collagen injection complications.

What are the signs, and when is a late filler lump urgent?

The usual sign of a filler granuloma or delayed-onset nodule is a firm lump at a previous injection site that appears, hardens or swells months or years after treatment. Most are not emergencies, but they should be examined by a doctor before anything is done.

Typical features:

• A firm or rubbery lump, or several, where filler was placed.
• Redness, a red-brown colour, tenderness or warmth in inflammatory nodules.
• Swelling that comes and goes, sometimes flaring during or after an illness.
• Lumps that become harder over months as scar-like tissue forms (Funt and Pavicic, 2013).

See a doctor promptly if a lump is new or growing, and on the same day if it is red, warm, tender or increasingly painful, or if old filler sites swell after an illness.

Go to an emergency department now if you have:

• Spreading redness with fever, or feeling very unwell.
• Severe or escalating pain.
• Skin turning pale, dusky or mottled.
• Any change in vision.
• Swelling of the lips, tongue or throat, or difficulty breathing.

What not to do: do not massage, squeeze or puncture the lump, and do not start leftover medicines or creams, unless your doctor advises it. Pressing on an inflamed or infected lump can make it worse. For puffiness without a distinct lump, see filler swelling: what is normal.

How are filler granulomas and delayed nodules diagnosed?

A filler granuloma is diagnosed by examining a tissue sample under the microscope; a delayed-onset nodule is assessed first by history, examination and, where useful, ultrasound. Because a granuloma, an infected lump and plain excess filler can look alike on the surface, the aim is to work out which one is present before choosing a treatment.

• History: every filler you have had, with products, dates and areas; recent illness, dental work or vaccination; autoimmune or allergic conditions; and current medicines.
• Examination: whether the lump is hot, red or tender, how deep and well defined it is, and whether other treated areas are affected.
• Ultrasound: high-frequency ultrasound can show whether a lump is filler, swelling, a collection of fluid or something else, and how deep it sits. DermNet notes it is especially useful for cosmetic fillers, where a biopsy is not desirable.
• Tissue sample (biopsy): the confirming test for a granuloma, showing immune cells and giant cells around the filler (Lee and Kim, 2015).
• Culture: fluid or tissue may be tested for bacteria where infection is suspected, although low-grade infection often gives a negative result (Funt and Pavicic, 2013).

Not every lump needs a biopsy. Many are managed on the history, examination and scan, with a sample reserved for lumps that persist or do not behave as expected. You can see how scanning works in the ultrasound filler mapping video.

How are filler granulomas and delayed-onset nodules treated?

Filler granulomas and delayed-onset nodules are treated according to their cause: possible infection is dealt with first, hyaluronic acid filler can be dissolved, and persistent inflammatory lumps may need medicine prescribed by a doctor. Expert groups do not fully agree on the order, and treatment is often staged over weeks with a review between steps (King and colleagues, 2016).

• Watchful waiting: a lump that can be felt but not seen, and is not inflamed, may simply be reviewed.
• Treating infection first: for inflamed nodules, published algorithms begin with a course of medicine for infection lasting weeks, because anti-inflammatory treatment given too early can worsen an infected lump.
• Dissolving the filler: for hyaluronic acid, an enzyme (hyaluronidase) can remove the material the body is reacting to; published guidance suggests considering it when an inflamed lump has not settled with other treatment, although the evidence is limited. See dissolving filler.
• Anti-inflammatory medicine injected into the lump: the usual first treatment for a confirmed granuloma. It can thin the skin, so small, spaced doses are used.
• Other medicines: specialists sometimes add tablets or other injections for lumps that return.
• Surgery: a later option, because granulomas often have ill-defined edges and are hard to remove completely (Lee and Kim, 2015).

Evidence for lasers in filler nodules is limited, so they are considered case by case. No treatment can promise that a granuloma will clear, and some need several rounds. If you later want filler again, see filler after dissolving.

How does Dr Sin Yong assess a delayed filler lump at SkinRev Lab?

At SkinRev Lab, Dr Sin Yong, medical adviser, assesses a delayed filler lump by taking a full filler history, examining the lump and other treated areas, and scanning with ultrasound where useful, before anything is dissolved or added. Doing nothing is always one of the options explained, and you can be assessed wherever you were first treated.

What to bring, if you have it:

• Product names, dates, amounts and areas for every filler session.
• Photos from before the lump appeared and since.
• Details of any recent illness, dental work or vaccination, and any treatment already tried.
• A list of medicines, allergies (including bee or wasp stings) and medical conditions.

What the consultation covers:

• Whether the lump looks like filler, inflammation, infection or something unrelated to filler.
• Whether to wait and review, dissolve hyaluronic acid filler, start medicine or refer.
• What is realistic, how many visits may be needed and what cannot be predicted.

Under ultrasound, the enzyme can be placed directly into a hyaluronic acid deposit. Where a tissue sample, surgery or specialist medicine is the appropriate next step, Dr Sin Yong will refer you. For excess from non-dissolvable filler, Time Freeze Laser LCLR is considered case by case. Assessment and correction are priced at consultation.

SkinRev Lab is not an emergency department. If you have spreading redness with fever, severe or escalating pain, pale, dusky or mottled skin or any change in vision, go to an emergency department now and do not message or wait for the clinic.

How can you lower the risk of delayed filler lumps?

You can lower the risk of delayed filler lumps by choosing a doctor who cleans the skin thoroughly, uses conservative amounts at the planned depth, and asks about your health and past fillers before injecting. Nothing removes the risk entirely, and granulomas cannot currently be predicted, but published guidance points to these steps (King and colleagues, 2016; Funt and Pavicic, 2013).

Questions to ask before treatment:

• What exactly is the product, and will its name, batch and amount be written down for me?
• Can it be dissolved if there is a problem later?
• How is the skin prepared, and is the injection done through clean skin and not through the lining of the mouth or nose?
• How much is planned, and how long should I wait before any top-up?
• Is there old filler in this area, and should it be checked first?

Tell the doctor about:

• Autoimmune or allergic conditions and any medicines that affect the immune system.
• Any previous reaction to filler.
• A current infection, cold sore, or skin problem near the area.
• Dental work or vaccinations planned around the same time, so your doctor can advise on spacing.

Keep your own record of every filler treatment. Years later, knowing what was injected and where is often the most useful information a doctor can have. For a gradual build-up of product, see signs of too much filler.