- Acute anaphylaxis is rare but life-threatening.
- Incidence is increasing, with female preponderance.
- Usually type-1 IgE-mediated hypersensitivity.
- Foods: dairy products, nuts, seafood and fruits.
- Drugs: antibiotics, opioid analgesics and NSAIDs.
- Wasp or bee stings.
- Miscellaneous causes include latex and exercise, and it can also be idiopathic.
- Feeling of impending doom.
- Respiratory features include laryngeal oedema, stridor and bronchospasm.
- Cardiovascular features include palpitations, chest pain and loss of consciousness.
- Skin features include pruritus, urticaria and angio-oedema.
- Gastrointestinal features include lip and tongue swelling, nausea and vomiting, abdominal pain and diarrhoea.
- Mast cell tryptase is the only test indicated at the time of reaction to confirm the diagnosis.
- Subsequent investigations are directed at detecting the trigger agent.
- Acute management involves adrenaline IM, oxygen, parenteral hydrocortisone and parenteral chlorpheniramine.
- Admit to hospital.
- Subsequent management involves identifying the trigger and advising on avoidance.
- Prescribe EpiPen and educate patient about how and when to use it.
- Recommend a Medic Alert bracelet/necklace.
- Death is common in the elderly and asthmatics.
Contributed by Dr Aziz Sheikh, professor of primary care research and development, Division of Community Health Sciences, GP Section, University of Edinburgh.