Primary prevention

Probiotic supplementation during pregnancy and breastfeeding may reduce the risk of atopic disease; fish oil supplementation during pregnancy and breastfeeding may reduce risk of sensitization to food allergens.[43] Maternal allergenic food avoidance during pregnancy or lactation does not appear to reduce the risk of allergic or autoimmune disease.[43]

Early introduction of peanut and eggs into the infant diet can reduce the risk of those respective allergies.[44][45]​ Other common allergens can be introduced around the same time as well.[45]​ In infants with no history of egg allergy, and no, or mild-to-moderate atopic disease, peanut-containing foods can be introduced during weaning.[44] In infants with severe eczema and/or egg allergy, screening for peanut allergy should occur before introduction of peanut-containing foods.[44]

Precautions against exposure to insect stings includes closed footwear and thick socks when outside. Windows should be closed when driving and when at home (insect protection windows are recommended for the home). Drinking or eating outdoors requires special care, as honeybees seek all fluids, especially in hot weather, and European wasps seek the sugar in drinks. These recommendations are crucial for individuals with known allergies and individuals at high risk, such as children from allergic families or atopic children. Avoiding exposure to insect stings (e.g., bees, wasps, and ants) is recommended for the general population, as individuals might not be aware of their allergy. The US National Institute for Occupational Safety and Health has published information for employers and their workers about the risk of exposure to insects and scorpions, and prevention of stings and bites. CDC: insects and scorpions at work Opens in new window 

Medical personnel and high-risk patient groups (e.g., patients with spina bifida) can be protected from developing latex allergy by avoidance of latex-containing materials and catheters.[28]

Secondary prevention

Prevention of subsequent allergic reactions starts with clear identification of the causative allergen and allergen avoidance. Patient and caregiver awareness and education is crucial.[115]

For food allergies, awareness includes careful attention to food labeling, caution with takeout and restaurant foods, and an allergen-free environment. Many industrial countries, including the US, mandate the precise labeling of all foods. Restaurants will often specify special additives and ingredients. This is helpful as even traces of an allergen may be sufficient to trigger an allergic reaction. See Food allergy for further information.

Latex-free precautions are necessary in surgical or dental procedures in latex-allergic patients.[116] Medication allergies require a medical record alert and a MedicAlert bracelet or necklace. Possible cross-reactivity has to be considered as well.

Prevention of insect stings is crucial in allergic individuals. Venom immunotherapy is recommended for patients who have experienced severe systemic reactions to insect stings and have specific immunoglobulin E to venom allergens.[96] Elevated baseline serum tryptase is closely correlated with the risk of severe anaphylaxis to insect stings, and measurement of baseline serum tryptase may be useful in individuals with a prior history of suspected anaphylaxis from a bee or wasp sting.[71][117]

Prophylaxis with corticosteroids and/or antihistamines

Pharmacologic prophylaxis with corticosteroids and/or antihistamines may be considered for the prevention of recurrent episodes of anaphylaxis to specific agents in chemotherapy protocols.[12] The routine administration of corticosteroids and/or antihistamines is not recommended for the prevention of anaphylaxis in patients with prior radiocontrast hypersensitivity reactions.[12] However, premedication may be considered if there is a high level of perceived risk of anaphylaxis or comorbidities associated with a greater anaphylaxis fatality risk.[12]

Epinephrine (adrenaline) auto-injectors

It is usual practice to provide a prescription for two epinephrine auto-injectors after any episode of anaphylaxis due to the risk of severe anaphylaxis or a biphasic recurrence requiring multiple doses, although it may be reasonable to adopt a risk-stratified approach.[55][90] The patient or caregiver should carry both of them at all times and be familiar with their use.[83] For children at risk of anaphylaxis, the epinephrine auto-injectors should be prescribed in conjunction with a personalized written emergency plan.[83][91] American Academy of Pediatrics: allergy and anaphylaxis emergency plan Opens in new window

Based on a US Food and Drug Administration alert, patients and caregivers are advised to periodically review their auto-injector instructions and practise administration with a trainer device. Users of EpiPen® epinephrine auto-injectors should inspect their device prior to needing it to ensure the blue safety release is not raised and that the device can be easily removed from the carrier tube.[118]

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