Patients must be clearly informed before making any decision, not to worry them unnecessarily, but to allow an informed choice based on a realistic understanding of treatment. The nasolabial fold's anatomical position and rich vascularisation require rigorous technical mastery. When treatment is performed by an experienced doctor, undesirable effects are rare and generally minor. But they exist and must be discussed seriously and transparently.
What are normal side effects after a nasolabial fold injection ?
Most effects seen after a hyaluronic acid injection into the nasolabial fold reflect a local reaction : they occur naturally in response to introducing a foreign substance into dermal or subcutaneous tissue. These reactions are predictable, temporary and minor, resolving spontaneously within hours or days.
Expected reactions frequently include slight redness at the injection point, mild swelling along the fold or local tension. These arise from mechanical penetration by the cannula or needle and the gel's presence in previously untreated tissue. They are not complications, but common post-procedure effects anticipated and monitored by the doctor.
In some cases, localised bruising can appear, particularly if a small superficial vein was touched. This small bluish mark is harmless and fades within days. Avoiding anti-inflammatory and anticoagulant medication before injection is recommended to limit this risk.
Which post-injection side effects should prompt a consultation ?
When certain post-injection signs persist beyond 7 to 10 days or are accompanied by abnormal symptoms, medical reassessment is required. This does not necessarily indicate a serious complication, but a local reaction requiring treatment adjustment or simple monitoring.
Some patients describe feeling a nodule or small lump beneath the skin along the fold. This may reflect a temporary product accumulation, poor tissue integration or a slightly off-centre hyaluronic acid deposit. Most often, this irregularity diminishes spontaneously or can be corrected by gentle massage performed by the doctor.
What risks are associated with the product or injection technique ?
Certain undesirable effects can occur when the indication is incorrect, unsuitable hyaluronic acid is chosen or the injection technique lacks precision. When the gel is too volumising, too firm or injected too superficially, it can create an overcorrected appearance, with a ridge visible at rest or even a Tyndall effect — blue-grey discolouration beneath the skin associated with poor light diffusion through the product.
Although medically minor, this imperfection compromises aesthetic result quality. Prevention depends on detailed knowledge of the injected hyaluronic acid's physicochemical properties and complete technical mastery. If the result is considered unattractive, the product is resorbable.
Furthermore, using only a needle rather than a cannula can increase bruising or accidental intravascular injection risk. The cannula guarantees greater vascular safety than the needle, making it many doctors' preferred instrument for nasolabial fold treatment.
What are the rare complications of nasolabial fold injections ?
Although serious complications are rare, they exist and must be fully explained during consultation. One of the most feared is vascular occlusion, occurring when an injection compresses or blocks a blood vessel and prevents downstream tissue perfusion. This risk theoretically exists in the richly vascularised nasolabial region, particularly in patients with previous local surgery.
Warning signs include sudden pain, local pallor, a burning sensation or loss of sensation. In extreme untreated cases, this can cause skin necrosis or, very rarely, ophthalmic complications if embolism affects orbital circulation.
Every injecting doctor must therefore be trained to recognise early signs of vascular complications and have an emergency management kit, including sufficient hyaluronidase. Rapid intervention is decisive. Injected within minutes of the incident, the antidote often treats this complication without lasting damage.
Can an allergy or delayed reaction occur after an injection ?
Hyaluronic acid products used aesthetically are highly pure, non-animal-derived and exceptionally well tolerated. However, like any biological product, they can cause immune reactions in some patients.
Immediate allergic reactions are extremely rare, but when they occur they involve extensive swelling, itching or, in severe cases, anaphylaxis. The doctor must always ask about allergy history and be equipped to intervene if needed.
Granulomas are a chronic inflammatory reaction to a foreign substance. They can appear weeks or months after injection as an inflamed nodule, sometimes red or tender. Management involves medical treatment (local or systemic corticosteroids) or enzymatic treatment, depending on their nature.
These reactions remain exceptional, affecting fewer than 0,1 % of cases according to literature data.
Does skin quality influence side effects ?
Skin quality directly influences its response to injections, particularly around the nasolabial fold. Thin skin weakened by sun, age or pronounced laxity is generally more sensitive to injectable products. In this case, hyaluronic acid may take longer to integrate, sometimes with slight temporary product visibility or a transient local reaction.
Conversely, thicker or fibrous skin with substantial tissue density may react differently : overly superficial injection can cause small temporary nodules.
Careful skin quality analysis combined with a perfectly adapted technique is therefore essential. This not only prevents undesirable effects, but also ensures harmonious, natural correction and targeted management of possible reactions.
Do previous injections increase the risk of side effects ?
In patients who have already had nasolabial fold or other facial injections, side effects may be influenced by residual previous products, sometimes invisible on clinical examination. Certain older formulations or large injected amounts may have left areas of fibrosis or chronic inflammation that react unpredictably to a new injection.
It is therefore essential during the first consultation to reconstruct the patient's aesthetic history in detail and identify every previously treated area. If uncertainty remains, high-frequency ultrasound can visualise residual product deposits and adapt the injection strategy accordingly. This precision avoids unforeseen interactions and considerably reduces side effect risk.
