Updated | 31 March 2020 What allergic reactions happen when we are bitten by insects? The most common bites are from mosquitoes, flies, fleas and bedbugs and generally trigger mild local reactions : Ache; Itch; Redness; Swelling at the bite site. In about 10% of people exuberant local reaction to an insect bite with edema (swelling) at the site of the bite happen, being larger than 10 cm in diameter and usually persisting for more than 24 hours. These exuberant reactions are very annoying and should be treated, but they are not life-threatening, nor increase the likelihood of a serious allergic reaction in the next bites. Severe allergic reactions (anaphylaxis) caused by insects result almost all from the bites of bees and wasps (hymenopterans). What are the symptoms of hymenopteran poison allergy? In severe allergic reactions (anaphylaxis) the symptoms usually develop a few minutes after the bite and can have different severity degrees. Two or more organs or body systems area affected simultaneously, including: Skin; Upper and / or lower airways; Cardiovascular system; Digestive system. Signs and symptoms of anaphylaxis can include: Hives; Edema or swelling; General malaise; Nausea; Vomiting; Diarrhea; Abdominal pain; Wheezing; Stridor; Shortness of breath; Tachycardia; Dizziness; Confusion; Feeling faint; Cardiorespiratory arrest. What should be done when there is a severe allergic reaction? All people with a history of severe allergic reactions should be referred to an immunoallergology consultation to be studied and treated. The vaccine with the poison to which they are allergic is the only treatment currently capable of preventing future reactions. The authors of this text are the following allergologists from the Hospital da Luz network: Luís Miguel Borrego, Ana Morais Mendes, Ana Reis Ferreira, Andreia Ferrão, Carlos Braga, Cristina Lopes, Diana Pereira da Silva, Filipa Semedo, Isabel Costa Silva, João Gaspar Marques, Pedro Carreiro Martins, Marta Salgado, Nuno Sousa, Rosa Anita Fernandes, Susana Piedade 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.
