What is an allergic reaction in aesthetic treatments?
An allergic reaction is the immune system overreacting to a substance that is actually harmless. In aesthetic treatments, this substance may be the product injected or applied, ingredients in the product, a numbing cream, a local anaesthetic (a medicine that numbs an area), gloves or the skincare products used after the procedure.
Not every redness or swelling after a procedure is an allergy. The expected tissue response to a needle, laser or peel also causes redness and swelling. What usually suggests an allergy is itching, hives (raised, itchy patches), spreading beyond the treated area, or a rash that matches the borders of the area the product touched.
Which reactions are normal, and which may be an allergy?
| Usually expected (keep an eye on it) | Contact your physician | Emergency (call 112 immediately) |
|---|---|---|
| Mild redness and swelling in the treated area that gradually decrease | An itchy, raised rash or redness spreading beyond the area | Shortness of breath, wheezing, a feeling of tightness in the throat |
| Small bumps at the injection points that go down quickly | Itching, blisters or flaking where a cream or skincare product was applied | Rapidly increasing swelling of the lips, tongue, throat or face |
| Mild tenderness and a feeling of warmth | Swelling or redness appearing in the treated area days or weeks later | Hives over a large part of the body together with dizziness or feeling faint |
| Brief light-headedness during the injection that passes when you lie down | Itchy swelling of the eyelids, without shortness of breath | A rash together with confusion, a very fast and weak pulse or vomiting |
This table is a general guide and does not make a diagnosis. If you are not sure, call the physician who performed the treatment. Never wait if you have difficulty breathing or swallowing.
What is anaphylaxis? When should you call 112?
Anaphylaxis is a severe allergic reaction that affects more than one organ, can progress rapidly and can be life-threatening. It usually starts within minutes of contact with the substance. It is very rare in aesthetic treatments; however, recognising it early and treating it quickly saves lives.
Call 112 without waiting
- Shortness of breath, wheezing, a persistent cough or a feeling of tightness in the throat
- Rapidly increasing swelling of the lips, tongue, throat or face; difficulty swallowing or speaking
- Itchy hives or redness over a large part of the body together with feeling unwell
- Dizziness, fainting, confusion, pale and cold, clammy skin
- A fast and weak pulse, palpitations
- Sudden abdominal pain, nausea or vomiting together with a rash
If anaphylaxis is suspected, do not stay alone after calling 112. If you feel dizzy or faint, it is recommended that you lie on your back and raise your legs; if you are having difficulty breathing, stay in a sitting position. If you have an adrenaline auto-injector previously prescribed for you by your physician, use it as you were taught and still call 112. Even if the symptoms improve, you need to be assessed in the emergency department because they can come back.
Clinics performing these procedures are expected to be prepared for such rare emergencies, meaning emergency medicines and equipment are at hand and the team knows how to give first aid. It is a sensible question to ask before the procedure; this topic is covered on the page “A 10-Point Safety Checklist for Choosing a Clinic and Physician for Medical Aesthetics”.
When does an allergic reaction start, and how long does it last?
Allergic reactions can be roughly divided into two groups according to when they start. Rapid reactions usually start within minutes to a few hours of contact with the substance; hives, itching, facial swelling and, in its most severe form, anaphylaxis belong to this group. This is why you may be asked to wait in the clinic for a short time after injection treatments.
Delayed reactions, on the other hand, appear hours or days later. Contact dermatitis is a typical example: an itchy rash may become noticeable a day or two after contact with the product. Most mild reactions subside within days once the trigger is removed; however, how long they last varies depending on the person and the cause.
Noting when the symptom started helps your physician understand the type of reaction. It is enough to briefly write down which product you used and when, and where the rash started and where it spread.
Local anaesthetic allergy: is it really an allergy, or fainting?
Many people believe they are allergic to numbing medicines because they felt unwell at the dentist or during a procedure. However, comprehensive reviews show that true allergy to local anaesthetics is very rare. Most such events have other causes.
The condition most often confused with it is vasovagal fainting. The needle, pain, the sight of blood or anxiety can slow the heartbeat and lower blood pressure. The person turns pale, sweats, feels nauseous and dizzy, and sometimes briefly loses consciousness. When they lie down and their legs are raised, it usually improves within minutes, and it is not accompanied by itching, hives or shortness of breath.
The blood vessel-narrowing ingredient found in some local anaesthetic mixtures can also cause brief palpitations, trembling or restlessness; this is not an allergy either. Even so, the distinction should always be made by a physician. If you have had a problem with a numbing medicine before, describe it in detail; if necessary, your physician may refer you to an allergy specialist.
Serious allergic reactions are rare, but they can develop within minutes. Be sure to mention any known allergies before the procedure; if you develop shortness of breath or swelling of the lips or tongue, call 112 (or your local emergency number) without waiting.
Dr. Hamza GemiciMedical Director, DoktorClub · Aesthetic Medicine Physician
Contact dermatitis due to numbing creams and skincare products
Contact dermatitis is an itchy, red, sometimes blistering and flaking reaction to a substance the skin has touched. In aesthetic treatments, it can be caused by numbing creams applied before the procedure, antiseptic solutions, glove material, wound care creams, sunscreens or perfumed cosmetics.
A typical feature of this reaction is that the rash matches the borders of the area where the product was applied. Symptoms sometimes start not immediately but within a day or two. Some numbing creams can irritate the skin even without an allergy and cause temporary redness or paleness. Stop using the product you suspect and tell your physician its name.
Can you be allergic to filler, botulinum toxin or the enzyme hyaluronidase?
Serious allergic reactions to hyaluronic acid fillers and to botulinum toxin (commonly called “botox”) are rare. Swelling and redness that appear weeks or months after filler are, in most cases, not a classic allergy but a delayed reaction of the immune system or conditions due to other causes; these are described separately on the page “Filler Complications”.
Allergic reactions to hyaluronidase, the enzyme used to dissolve hyaluronic acid filler, have also been reported. Although rare, the risk may be higher especially in people who have been exposed to this enzyme before or who are allergic to bee or wasp stings. This is why it is important to tell your physician about any such history of allergy.
Telling whether swelling after filler is an allergy, expected swelling or a blood vessel problem requires an examination. For the course of expected swelling, see the page “Bruising and Swelling”, and for urgent circulation symptoms, the page “After Fillers: When Is It an Emergency?”.
What can your physician do?
- For mild, local reactions, they will examine the area, try to identify the suspected product and plan suitable treatment if necessary.
- For contact dermatitis, they may recommend stopping the triggering product and suitable skin care; if necessary, they may refer you to a dermatologist for patch testing.
- In anaphylaxis, the cornerstone of emergency treatment is adrenaline; it is given by the healthcare team in the clinic or emergency department, and the patient is kept under observation for a while.
- If a true allergy to a local anaesthetic or another medicine is suspected, they may refer you to an allergy specialist so that you can be treated safely in the future.
The physician who examines you decides which medicine is used and for how long. Starting antihistamines or steroid medicines on your own is not recommended, especially because they can mask the first signs of a severe reaction.
If you have had an allergic reaction, trying to find out what caused it is important so that you can be treated safely in the future. Ask your physician for a list of all the products and medicines used on you, and share this information with all your future physicians.
What can you do at home, and what should you avoid?
- If you have any symptom affecting breathing, swallowing or consciousness, do not wait at home; call 112.
- With a mild, local reaction, stop the creams and cosmetic products you suspect and do not scratch the area.
- Take photos of the rash and the swelling; note when it started and what you used.
- Do not use medicines left over from old prescriptions or creams recommended for someone else.
- Until the reaction has passed, do not have a new procedure on the same area or try a new product.
What can be done to reduce the risk of an allergic reaction?
- Before the procedure, mention all your allergies: medicines, local anaesthetics, latex, bee stings, foods, cosmetic products.
- Describe in detail any reaction you had during a previous aesthetic procedure, at the dentist or during an operation; if you know which product was used, say so.
- Mention any allergic conditions such as asthma, eczema or chronic hives, and the medicines you take regularly.
- Ask for the name and batch number of the product used to be recorded in your file; if there is a reaction, it will be known which product may be responsible.
- Ask whether the clinic is prepared for emergencies; have the procedure done by a physician in a healthcare facility.
- After the procedure, use only the skincare products your physician recommends; leave trying new cosmetics until after healing.
If you have had a reaction, see the page “What Should You Do If a Complication Occurs after an Aesthetic Treatment” for the next steps. If there is increasing redness, warmth and discharge in the area, infection rather than allergy may be suspected; on this subject, the page “Infection after Aesthetic Treatments” can help.
This page is for general information and does not replace an examination. With signs of a severe allergy, call 112 without losing time.
Questions to ask your physician
- Which products, numbing creams and skincare products will be used in this procedure?
- I felt unwell at the dentist before; was it an allergy or fainting, and what should we do before the procedure?
- I am allergic to bee stings; is this relevant with regard to the enzyme hyaluronidase?
- Does the clinic have emergency medicines and equipment for a severe allergic reaction?
- How long should I wait in the clinic after the procedure?
- For which symptoms should I call you, and for which ones should I call 112 directly?
- Can I see the name and batch number of the product used in my records?
- Do I need an allergy test; would you refer me to an allergy specialist?
Frequently asked questions
Is itching after filler a sign of allergy?
Mild, short-lived itching can be part of healing. If the itching comes with hives, spreading redness or increasing swelling, it may be an allergy and needs to be assessed by your physician. If it is accompanied by shortness of breath or swelling of the lips or tongue, call 112 immediately.
I think I am allergic to local anaesthetics; can I have an aesthetic treatment?
True allergy to local anaesthetics is very rare, and most episodes of feeling unwell in the past are related to fainting or anxiety. Even so, describe this history to your physician in detail. If necessary, your physician may refer you to an allergy specialist before the procedure.
What are the symptoms of anaphylaxis?
The most important symptoms are shortness of breath, wheezing, swelling of the lips, tongue or throat, widespread hives, dizziness, fainting and a fast, weak pulse. It usually starts within minutes and can progress rapidly. If you have even one of these symptoms, call 112 without waiting.
My face turned red after a numbing cream; is that normal?
Some numbing creams can cause temporary redness or paleness even without an allergy. If the redness becomes itchy, blistered or flaky, or lasts for days, it may be contact dermatitis. In that case, stop using the cream and tell your physician the name of the product.
Can you be allergic to botulinum toxin?
A serious allergic reaction to botulinum toxin is very rare. Even so, if widespread itching, hives, swelling of the face or tongue or shortness of breath occurs after the injection, an allergy should be considered. If you have shortness of breath, call 112 immediately.
I fainted during the procedure; is that an allergy?
Most often, no. Vasovagal fainting due to the needle, pain or anxiety is common and usually improves quickly when you lie down. If fainting is accompanied by hives, shortness of breath or facial swelling, an allergy should be considered and an emergency assessment carried out.
I had an allergic reaction; can I take the allergy medicine I have at home?
With severe symptoms, taking a medicine does not replace calling 112. With mild reactions too, your physician should decide which medicine is suitable. A medicine you start on your own can make it harder to monitor how the symptoms develop.
Sources
- World Allergy Organization Anaphylaxis Guidance 2020 (Cardona V et al.). World Allergy Organ J 13(10):100472 — World Allergy Organization Journal, 2020
- IgE-mediated allergy to local anaesthetics: separating fact from perception: a UK perspective (Bhole MV et al.). Br J Anaesth 108(6):903–911 — British Journal of Anaesthesia, 2012
- Allergic Complications of Hyaluronidase Injection: Risk Factors, Treatment Strategies, and Recommendations for Management (Guliyeva G et al.). Aesthetic Plast Surg 48(3):413–439 — Aesthetic Plastic Surgery, 2024
- Late-Onset Reactions after Hyaluronic Acid Dermal Fillers: A Consensus Recommendation on Etiology, Prevention and Management (Baranska-Rybak W et al.). Dermatol Ther (Heidelb) 14(7):1767–1785 — Dermatology and Therapy, 2024
- Anaphylaxis — NHS
- Contact dermatitis — NHS
Medical Aesthetics Expert Board
This article has been reviewed by the DoktorClub Medical Aesthetics Expert Board.
