Food for thought
Food induced anaphylaxis is the leading cause of anaphylaxis treated in emergency departments and is increasing in prevalence.
A recent Australian study found that more than 10% of 1 year old infants had IgE-mediated food allergy. Admissions to hospital with anaphylaxis that is mainly attributed to food allergy have increased in the last decade, particularly in young children. Despite the emergent nature of anaphylaxis and its potential for mortality and morbidity, anaphylaxis continues to be under-recognised and inadequately treated in emergency departments.
The most common causes of food allergy are:
• Peanuts and tree nuts
• Seafood
• Egg
• Milk
• Sesame seeds; and
• Wheat.
While many of those allergic to milk, egg, wheat or soy outgrow their allergies by school age, those allergic to nuts/peanuts, seeds or seafood usually have persistent allergy into adulthood. Asthmatics, adolescents and those with a prior reaction are at increased risk for more severe anaphylactic reactions.
Clinical presentations of food-induced anaphylaxis vary between individuals and may manifest in multiple physiological systems and could include:
• Pruritus, urticaria, flushing, rash, angioedema
• Eye lid oedema and erythema, conjunctival injection
• Rhinorrhoea, sneezing, nasal congestion or itching
• Throat pruritus and/or tightness, stridor, hoarseness, dysphonia
• Cough, wheezing, dyspnoea, chest tightness, cyanosis
• Pruritus and/or oedema of the lips/mouth/tongue, metallic taste, dysphagia
• Nausea, vomiting, crampy abdominal pain, diarrhoea
• Tachycardia, arrhythmia, dizziness, syncope, chest pain, hypotension, shock
• Anxiety, headache, seizure, altered consciousness
• Urinary/faecal incontinence, diaphoresis, lower back pain, uterine contractions in women, sense of “impending doom”.
The mainstay of treatment for any anaphylactic reaction is the timely administration of adrenaline. Multiple reports on food-induced anaphylaxis occurring in the community have identified underutilisation of adrenaline, with 12% of food induced anaphylactic reactions requiring more than one dose.
Evidence from a study by Järvinen et al, showed that most second doses of adrenaline administered by health professionals had favourable outcomes where milk, egg and peanuts were the triggers and asthma was a predisposing factor.
With a growing population of food allergic adults and children, education is needed to identify the clinical presentation of anaphylaxis and to encourage the use of adrenaline as first-line treatment for anaphylaxis.
Useful URL
Australasian Society of Clinical Immunology and Allergy (ASCIA)
www.allergy.org.au