Anaphylaxis is a severe and potentially life-threatening reaction which may be the result of hypersensitivity.1 The hypersensitive reaction may be generalised or systemic, and tends to occur within minutes. It can be considered an allergic reaction, which may or may not have an immunological basis.2
The airway is often compromised as a result of pharyngeal or laryngeal oedema causing breathing difficulty. Increased respiratory rate or bronchospasm can cause these breathing difficulties. There might be evidence of circulatory compromise, such as hypotension and an increased heart rate. In most cases of anaphylaxis, skin and mucosal changes occur. Skin changes include flushing and urticaria. Symptoms can worsen rapidly.
It is of note that the incidence of anaphylactic reactions in the UK is increasing, according to data from the Resuscitation Council (UK).2
Patients that have previously had an allergic reaction may be at an increased risk of developing an anaphylactic reaction. There is an increased risk of anaphylaxis associated with other comorbidities, such as asthma. The risk of anaphylaxis is increased if asthma is poorly controlled.2