September 8, 2022 Angioedema most often affects the face, lips, and/or tongue, but it can also occur on the hands, feet, genitals, respiratory tree, or digestive system. It manifests as a usually localized swelling, originating in the deep layers of the dermis and submucosa , resulting of an increased vascular permeability with passage of intravascular fluid into the tissues. Angioedema can be hereditary or acquired . In both cases, it is characterized by an abnormal complement response, in which there is a deficiency or dysfunction of the C1 inhibitor, protein that regulates the classical complement activation pathway. Angioedema can also be acute or chronic , in this case when it lasts longer than six weeks. Causes of acute angioedema Acute angioedema is caused by exposure to food, animal, drug, poison, and/or pollen allergens . In more than 90% of cases, it is mediated by mast cells. These mechanisms include severe allergic reactions mediated by immunoglobulin E (IgE) and are accompanied by acute urticaria. Acute angioedema can also result from direct stimulation of mast cells without involving IgE, the main causes of which are drugs such as opiates, non-steroidal anti-inflammatory drugs, and radiopaque contrast agents. Angiotensin converting enzyme (ACE) inhibitors can directly stimulate the release of bradykinin into the circulation. In these cases, the face and upper respiratory tract are the most affected regions, urticaria is not common, and angioedema may appear soon after the beginning or only years after the treatment. Causes of chronic angioedema The cause of chronic angioedema is often unknown . The possibility of being due to regular ingestion of a drug or chemical compound (eg preservatives, additives, “natural” substances) must always be excluded. Another cause of chronic angioedema can be a deficiency, either inherited or acquired, of complement factor C1. IgE-mediated mechanisms are rare in chronic angioedema, which tends to occur in isolation, without urticaria. Symptoms Edema is usually asymmetrical and slightly painful . Often affects the face, lips and/or tongue, but can also occur on the hands, feet and/or genitals. When it reaches the respiratory system, it can cause dyspnea (respiratory discomfort) and stridor (inspiratory noise), which can be serious and potentially fatal. Edema of the digestive system can cause nausea, vomiting, abdominal pain and/or diarrhea. Regarding duration: Mast cell-mediated angioedema develops over minutes to hours and is often accompanied by other allergic manifestations such as pruritus, flushing, papules, erythema, bronchospasm, and/or anaphylactic shock, a serious and potentially life-threatening condition that requires immediate intervention. Bradykinin-mediated angioedema develops over hours to days and is usually not accompanied by other allergic reactions. Diagnosis of angioedema The diagnosis is clinical, based on a thorough history and on objective examination. In a cute angioedema , the cause is often obvious, self-limiting, and isolated, so additional diagnostic tests are not necessary. In chronic angioedema , a thorough evaluation of drugs and diet is warranted. If there is a family history, it is important to order C1 inhibitor levels to exclude hereditary or acquired angioedema. Angioedema treatment In the treatment of angioedema, the most important measure is to ensure airway patency . In addition to avoiding exposure to the causative allergen, the most commonly used drugs for this purpose are antihistamines, corticosteroids and, in more severe cases, adrenaline. If pharmacological treatment is not sufficient, orotracheal or nasotracheal intubation, tracheotomy or even cricotomy are life-saving measures. When to see an otolaryngologist In most cases, angioedema is a benign condition. However, whenever there is an important reaction with urticaria and/or exuberant edema, respiratory and/or swallowing difficulties, care in a hospital emergency department are required. This article was written by the Hospital da Luz otorhinolaryngology team. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
