Prevention
A number of studies have demonstrated that early introduction of peanuts reduces the risk of developing peanut allergies by up to 80% with sustained effects through early childhood36-41. This risk reduction has also been observed by many studies for early introduction of egg allergy. When hen’s egg is introduced to infants by 1 year of age, cumulative incidence of egg allergy was reduced at 3 years from 2.2% to 0.2%42. For other food allergens, the evidence is weaker and further studies are needed to determine whether early introduction decreases risk of allergy. The EAT Study found no effect of early introduction of milk, wheat, fish and sesame at 4–6 months on risk of food allergies in the intention to treat analysis.43 However, a more recent randomized controlled study found that the introduction of cow’s milk formula at 1-2 months reduced the cumulative incidence of milk allergy at 6 months from 6.8% to 0.8%.44
Additionally, a pilot study demonstrated that compared to placebo (flax seeds) daily supplementation of a blend of 16 unique allergenic foods in infants 5-11 months of age over a 28-day period was well-tolerated with no significant differences in AEs. 45 These findings suggest that the early introduction of single allergens, or simultaneous introduction of multiple allergens, may be protective against FA. However, besides allergen types, questions such as age of allergen introduction, allergen amounts, and infant demographics (high risk or general population) needs further evaluation.46 Other birth cohort studies, such as PARIS and ELFE are evaluating whether breastfeeding, consumption of different infant formulas such as regular, pre-/probiotics, partially hydrolyzed with hypoallergenic label, extensively hydrolyzed, soya, long chain poly unsaturated fatty acids (docosahexaenoic acid, arachidonic acid, and  eicosatetraenoic acid) play a role in the prevention of FAs.47,48
While early ingestion of food generally promotes the induction of natural tolerance, exposure of food allergens through an impaired skin barrier may promote the development of FA49. Unsurprisingly, dry skin, as measured by trans-epidermal water loss (TEWL), and atopic dermatitis (AD) have been identified as risk factors for the development of FA50,51. Recent evaluation of moisturizers to prevent dry skin and reduce TEWL have presented conflicting results52-55; however, this may be due to the types of moisturizers used. The use of moisturizers containing food components such as olive oil and oat were associated with an increased risk of FA development, with each additional weekly application of moisturizers corresponding to an adjusted odds and risk ratio of 1.20 and 1.47, respectively56,57. In contrast, studies employing moisturizers, such as tri-lipid creams, that do not contain food allergen components and more closely mimic the skin microenvironment have indeed observed reductions in food sensitization58 accompanied by increases in peanut-specific IgG, decreases in peanut-specific IgE, and a shift towards tolerogenic T cells52,53. A multi-center, phase II trial, the SEAL Study (Stopping Eczema and Allergy, NCT03742414), is investigating the efficacy of proactive daily tri-lipid skin barrier cream or commercial moisturizer with concomitant topical steroid use as needed compared to reactive care only in infants who have already developed AD or eczema by 12 weeks of age. The trial seeks to determine whether such interventions are able to reduce the occurrence and severity of atopy in early life, and, ultimately, prevent the subsequent development of FA. Further investigation is needed to determine optimal strategies across a multitude of topical agents that vary significantly in composition.