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.