Angioedema After an Injectable Procedure

Almost every injectable procedure leaves some swelling, and the patient learns to expect it. That habit creates a risk: when the swelling is of another kind, faster, deeper and disproportionate, it can be mistaken for "normal" swelling and go without the attention it deserves. Angioedema is rare, but it can threaten the airway, and anyone seeing patients in an office needs to know how to recognize it and act. This guide covers the definition, differential diagnoses, signs of severity and how to organize care, at a review level. Actions and medications are decisions for the qualified professional, following the label and the rules of their professional council.

What is angioedema?

Angioedema is a sudden swelling of the deeper layers of the skin and mucous membranes, caused by increased vessel permeability. It tends to affect the lips, eyelids, tongue, cheeks, hands and, in the most severe cases, the larynx. It can come with hives, but also occurs without them.

There are two main mechanisms, and the difference guides the response:

• Histamine-mediated: the allergic or pseudoallergic type, which usually responds to antihistamines and corticosteroids, and is part of the spectrum of the hypersensitivity reaction.
• Bradykinin-mediated: non-allergic, related to some medications or to hereditary conditions, and does not respond well to the usual allergy treatments.

In the office, there is no need to settle the mechanism on the spot. The urgent question is a different one: is the airway at risk?

How to tell it apart from other causes of swelling

A swollen face after a procedure has several possible explanations. The table organizes the main ones.

The progression from angioedema to anaphylaxis is the main reason for care. See anaphylaxis in the facial harmonization office. Swelling that appears late is covered in delayed swelling after hyaluronic acid.

What can trigger angioedema after a procedure

Often the trigger is not the procedure itself. It helps to think in categories:

1. The injected product, through a reaction to the gel or to one of its components. The discussion is in allergy testing for fillers.
2. Anesthetics, local or topical, or components of their formulations. See local anesthetic allergy in facial harmonization.
3. Medications taken afterward, such as painkillers and anti-inflammatories, and some blood pressure drugs, which can cause angioedema through their own mechanisms.
4. Infections, viral or bacterial and recent, which stimulate the immune system.
5. Foods, stings and other allergens unrelated to the session.
6. Hereditary conditions, which can be triggered by trauma and procedures.

That is why the medical history should include a history of unexplained swelling, of hives and of continuous medication use.

Signs of severity and what to do on the spot

What decides the response is the risk to the airway and circulation. The warning signs are:

• swelling of the tongue, throat or uvula;
• hoarse voice, a feeling of tightness in the throat, difficulty swallowing;
• wheezing, cough and shortness of breath;
• intense dizziness, cold skin or pallor, drop in blood pressure;
• widespread hives and generalized itching;
• vomiting and abdominal pain along with the swelling.

If the swelling is isolated, mild and without signs of severity, the professional assesses it, observes for an appropriate time and instructs the patient in writing on when to seek emergency care. Even in these cases, documenting it and following up the next day are good practice.

What about hyaluronidase?

When the likely trigger is the hyaluronic acid gel, dissolving it with hyaluronidase may be considered, at the professional's discretion, after assessing the picture and the patient's safety. It is not a treatment for angioedema itself, and it does not replace clinical stabilization or referral. Before using it, remember that the drug itself can cause a reaction, and see hyaluronidase: allergy and testing and hyaluronidase in the office.

Common mistakes

1. Treating everything as "normal" swelling. Swelling that does not follow the pattern deserves reassessment.
2. Discharging the patient too early. Reactions can progress in the following minutes or hours.
3. Discharging without written instructions. The patient needs to know how to recognize the warning signs.
4. Forgetting the medication history. Blood pressure drugs and other medications are known triggers.
5. Not investigating afterward. A first episode deserves assessment by a specialist before any new exposure.

How to talk with the patient

Records and follow-up

Record the time of onset, symptoms, vital signs, actions taken, medications used, the response, instructions given and who accompanied the patient. Contact them the same day and the next day. Refer for allergy or medical evaluation when there is suspicion of a reaction to the product, of recurrent angioedema or of a hereditary cause. Document it in the patient record and update the informed consent before any re-injection. For a relevant event, consider reporting it, as covered in adverse event reporting to Notivisa (Anvisa's reporting system in Brazil).

Where Harmy comes in

Written discharge instructions

Every patient who had swelling outside the usual pattern should leave with written instructions: the signs that call for an emergency, the office phone number, the emergency service number and the advice not to be alone in the first hours. Also arrange an active follow-up contact the same day and the next day, and record the answers. This simple routine closes the care loop and protects both the patient and the professional.