Approach
Treatment of many allergic diseases is well established; however, treatment of food allergy still relies heavily on avoiding food allergens and reversing immune responses with epinephrine (adrenaline). Food allergy education for patients and carers is vital to help the successful implementation of these strategies. It is important that patients and carers are at all times alert for an allergic reaction caused by accidental ingestion. Reports of accidental exposure to the causative allergen range from 7% to 75% following diagnosis.[71] An individualised written allergy action plan may be beneficial to patients, parents/carers, and healthcare providers in preparing for treatment of an allergic reaction to food.[72] AAP: allergy and anaphylaxis emergency plan Opens in new window
Treatment of accidental ingestion of food allergens
Management of an accidental reaction to foods includes antihistamines for milder reactions and then epinephrine (adrenaline), antihistamines, and other treatment modalities for more severe reactions. The management of acute anaphylaxis requires immediate intervention with supportive and specific care.[73][74][75] The sudden onset of respiratory or cardiovascular compromise, usually with a history of allergen exposure (in presumably sensitised patients), with skin rash, wheezing and inspiratory stridor, hypotension, anxiety, nausea, and vomiting, should prompt immediate treatment.
An airway should be established and maintained. Patients with severe airway obstruction may require intubation.
Oxygen should be given and saturation monitored with pulse oximetry.
Epinephrine (adrenaline) should be given intramuscularly every 5 to 15 minutes, in appropriate doses as necessary, depending on the presenting signs and symptoms of anaphylaxis, to control and prevent progression to respiratory distress, hypotension, shock, and unconsciousness.[76][77] In refractory anaphylaxis with progressing systemic signs, treatment may best be facilitated by intravenous infusion of epinephrine (adrenaline). For cardiopulmonary arrest during anaphylaxis, high-dose epinephrine (adrenaline) and prolonged resuscitation efforts are encouraged, if necessary.[78]
The patient should be placed in a recumbent position and the lower extremities elevated.
Venous access for giving medication intravenously should be established.
Intravenous normal saline for fluid replacement and treatment of vasogenic shock should be instituted.
Specific measures to consider after epinephrine (adrenaline) administration include:[78][79][80]
H1- and H2-antagonists for cutaneous and gastric symptoms
Nebulised beta-2 agonist for bronchospasm resistant to epinephrine (adrenaline)
Systemic corticosteroids
Vasopressors for persistent hypotension
Glucagon for patients taking beta-blockers
Atropine for symptomatic bradycardia
Transportation to an emergency department or an intensive care facility.
For cardiopulmonary arrest during anaphylaxis, high-dose epinephrine (adrenaline) and prolonged resuscitation efforts are encouraged, if necessary.[78] Patients with severe airway obstruction may require intubation.
For rhinoconjunctivitis and symptoms from accidental ingestion limited to localised urticaria or pruritus, treatment with an oral antihistamine may be sufficient. Additional at-home management may consist of non-emergent therapy comprising:
Bronchodilator
Relaxes bronchial smooth muscle by action on beta-2 receptors with little effect on heart rate
Effective when wheezing is present, and may be given in a nebulised form with supplemental oxygen if needed
H2 antagonists
Work by competitive inhibition of histamine at H2 receptors of the gastric parietal cells, which inhibits gastric acid secretion and reduces gastric volume and hydrogen ion concentration
Reported to be more effective management of cutaneous symptoms than treatment with H1 antagonist (antihistamine) alone
Epinephrine (adrenaline) portable auto-injectors for self-injection.
For purposes of differentiating local versus systemic reactions, anaphylaxis herein is defined as an acute, severe, life-threatening allergic reaction in pre-sensitised people, leading to a systemic response caused by the release of immune and inflammatory mediators from basophils and mast cells.
A prescription for two epinephrine (adrenaline) auto-injectors must be given after any episode of anaphylaxis.[81][82] The patient or carer should carry both at all times and be familiar with their use.[77] For children at risk of anaphylaxis, the epinephrine (adrenaline) auto-injectors should be prescribed in conjunction with a personalised written emergency plan.[72][77] AAP: allergy and anaphylaxis emergency plan Opens in new window
Avoidance of food allergens
Patients should be educated regarding strict avoidance of the causative food allergen. Involvement of a dietician in this process is often very helpful, as poorly prepared elimination diets may lead to malnutrition. Successful avoidance relies on specific identification of the causative food allergen in the patient; recognition of cross-reacting foods; education of the patient and/or carer about avoidance measures, with emphasis on hidden food allergens or additives; and a willingness of the educated patient and/or carer to read labels carefully and give particular attention to hidden ingredients when eating at restaurants in order to prevent accidental exposures.[3]
US food labelling laws passed in January 2006 now require manufacturers to list the names of major allergens as ingredients in common terms; however, vigilance by the patient and carer is paramount in successful avoidance.[1][3] Those ingredients that must be listed are milk, egg, fish, crustacean shellfish, tree nuts, wheat, peanuts, and soyabeans. Food labelling laws in the European Union have gone even further. In addition to the foods mentioned above, sesame, gluten-containing grains (rye, barley, oats) and wheat, mustard, celery, molluscs, lupin, and sulphites (used as preservative) must be identified separately.[83]
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