Post-injection erythema
This means that there is a problem with blood circulation in the injection site. Excessive pressure may be the cause. At this stage, quick removal of pressure may solve the problem but if too late, necrosis may occur. If necrosis has not occurred but reduced circulation continues, infection can set in. Once infected, the injection site may produce pus and become swollen or bruised. Erythema occurring at this stage can lead to skin discoloration when exposed to sunlight.
Erythema, infection, hyperpigmentation and necrosis occur on a continuum. Each are not separate but occurs on a progressive course. Infection may arise from various factors; inadequate sterilization of equipment or unhygienic storage conditions of injectable materials, an excessively high dose injection, injection near acne, and patient touching the injection site, etc. The biggest cause of infection is overdose injection. I see the largest number of cases with infection caused by injection of excessive amount of filler.
After injection, vascular obstruction is another common side effect. Necrosis and blindness may be the most serious problems with filler injections. Underestimating the seriousness of post-injection erythema may lead to necrosis. Immediate measures should be taken to prevent necrosis.
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Tissue Reaction
Tissue reactions may precede granuloma. The injection site alternates between swelling and subsiding or turns red. Swelling is not limited to the injection site and spreads to surrounding areas. Swelling persists even after dissolving the injected filler. This is a key characteristic of tissue response. And swelling recurs whenever the patient feels fatigue or is unwell. When the filler is removed with aspiration, a new area may suddenly be affected by edema.
Such tissue responses may have various causal factors but seem to be part of an immunological response. I believe that the injected filler sensitizes the response and repeatedly triggers the response which leads to histological changes. The affected area becomes hardened, which eventually leads to granuloma.
There are two causes to granuloma. One is repeated irritation and the other is inadequate removal of the filler followed by unnecessary irritation of the injection site. I emphasize again that the key manifestation of tissue response is repeated and persistent swelling without pain. Symptoms resemble those of dermatitis and the injection site gradually hardens.
It is difficult to predict tissue response immediately after injection. However, one can sense a likelihood of tissue response by initial swelling. Edema usually subsides within 48 hours after injection. If it persists after 48 hours, initial swelling should be suspected. If swelling persists despite little damage to the skin, the filler may be toxic or have problematic composition. Toxicity may be related to problems with the manufacturing process, crosslinking, impurities in the syringe or excessive endotoxin, etc. Not much can be done about toxicity related to the product’s chemical composition.
Swelling that naturally disappears after 48 hours, does not cause a problem. There are some filler products that cause more swelling than others. It is advisable to reduce the dose to 60-70% as severe swelling may follow a full dose injection. If excessive and frequent swelling is seen, use hyaluronidase as quickly as possible. Once the window for possible dissolution passes, hardening sets in. Dissolving is easy in the early phase as the injected filler is not yet capsulated. If swelling takes place over 5 times in one year, capsulation may have already occurred. If not addressed quickly, hardened filler has to be removed through aspiration.
With bacterial infiltration, the injected filler may act as a large foreign body where the bacterial colonies form biofilms (a biofilm can form around a filler or silicone implant). In a normal tissue, bacterial infiltration can be countered by white blood cells but the filler works as a protective barrier for bacteria.
Most filler products are HA fillers and one may think they are easily removable with hyaluronidase. But this is not always true. Once the injected filler is capsulated, it is difficult to dissolve it. If the filler stays as a whole block it is easy to dissolve but if each particle is capsulated, dissolving becomes very difficult. In particular, multiple injections given in separate areas increase the filler’s contact area with tissues. When a filler with high likelihood of tissue response is injected this way, more severe responses may occur. Capsulated filler material does not dissolve with hyaluronidase injection and remain in the patient’s body to cause inflammatory response whenever the patient is unwell.
The best remedy for such cases is surgical removal. However, this leaves a large scar which patients are averse to. As a method with minimal scarring should be used for filler removal, aspiration is recommended.
Overly aggressive treatments
Seasoned doctors may become overly aggressive in treatment. The same filler that does not cause problems in small doses may cause vascular obstruction in larger doses. Seasoned doctors also seek new indications. Trying to expand indications is not a problem as long as it is based on profound research. However, it can be risky without sufficient preparation. It is dangerous to perform treatments solely based on one’s feelings or unverified opinions. I advise fellow doctors to research extensively before applying filler products to a new indication.
Conclusion
The more experience I get, I realize that filler procedures are very difficult. Experience teaches you how easily necrosis or vision loss can occur with filler procedures and makes you feel more fearful of the procedure itself.
In the next article, we are going to take a look at serious side effects of dermal fillers such as vascular injury, necrosis and blindness in greater detail.
-To be continued-
