Allergy
Food Allergy
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Food Allergy
See Also
Anaphylaxis
Pollen-Food Allergy Syndrome
Cow's Milk Allergy
Environmental Allergen
s
Epidemiology
Incidence
of Food Allergy
Adults: 2-3%
Children: 4-5%
Up to 15% of parents believe their children have Food Allergy, but most cases are unproven
Prevalence
of most common specific food allergens
Milk Allergy: 0.9% (up to 6% in studies based on parent or self-report)
Egg Allergy: 0.3% (up to 1% in studies based on parent or self-report)
Seafood allergy: Up to 2.8% of adults (based on parent or self-report)
Peanut allergy: 0.6% (based on parent or self-report)
Tree nut allergy: 0.4% (based on parent or self-report)
Risk Factors
Family History
of atopic disease (
Atopic Dermatitis
,
Asthma
,
Allergic Rhinitis
)
Tick Bite
(lone star tick) predisposes to
Alpha-gal Reaction
Sensitization to galactose-alpha-1,3-galactose (alpha-gal), found in both ticks and red meat
Results in severe, sudden,
Allergic Reaction
(
Urticaria
,
Anaphylaxis
) to beef, lamb, pork
Causes
Common Food Allergies
Children
Cow's Milk Allergy
Egg Whites
Wheat
Soy
Peanuts
Adults
Crust
aceans (e.g. shrimp, lobster)
Tree nuts
Peanuts
Fish
Causes
Food Allergies associated with
Anaphylaxis
Nuts (allergy often seen in
Atopic Patient
s)
Peanuts (legume)
Tree nuts
Pistachios
Walnuts
Cashews
Almonds (and marzipan)
Hazelnuts or filberts
Macadamian Nuts
Pecans
Brazil nuts
Pine nuts
Fish
Shellfish
Crab
Crayfish
Prawns or shrimp
Lobster
Seeds
Sesame seeds
Sunflower seeds
Caraway seeds
Causes
Cross-reactivity with contact or air-borne allergens
See
Oral Allergy Syndrome
Latex Allergy
Banana
Kiwi
Avocado
Birch pollen allergy
Carrot
Celery
Hazelnuts
Parsnips
Potatoes
Fresh fruit (apples, cherries, nectarines, peaches, pears)
Grass pollen
Kiwi
Tomato
Ragweed pollen
Bananas
Melons (canteloupe, honeydew, watermelon)
Pathophysiology
Initial reaction (Sensitization)
IgE antibodies produced to food
Subsequent Reaction
IgE fixed to
Mast Cell
s in Skin, GI, Respiratory
Reacts to allergen
Releases
Histamine
Chemotactics attract
Eosinophil
s
Prostaglandins and leukotrienes are released
Types
Clinical Presentations of Food Allergies
Emergent presentations
Food-induced
Anaphylaxis
Laryngeal
Angioedema
Skin reactions
Acute Urticaria
(IgE mediated)
Allergic Contact Dermatitis
(cell-mediated)
Angioedema
(IgE mediated)
Contact Urticaria
(IgE and non-Ige mediated)
Gastrointestinal food allergies
Dietary Protein
-induced
Proctocolitis
(non-IgE mediated to milk in infants)
Eosinophilic Esophagitis
(IgE and non-IgE mediated)
Food protein-induced enterocolitis (non-IgE mediated)
Immediate GI
Hypersensitivity
(IgE mediated)
Oral Allergy Syndrome
(cross-reactivity among foods; prevented by cooking offending food)
Symptoms
Skin
Urticaria
(
Hives
)
Atopic Dermatitis
Respiratory
Allergic Rhinitis
Asthma
Gastrointestinal
Vomiting
Blood in stool
Diarrhea
Anaphylaxis
Differential Diagnosis
Postprandial collapse
Airway Foreign Body
Non-allergic food reaction
Monosodium glutamate
Sulfite reaction
Scombroid Fish Poisoning
(vasoactive amines)
Differential Diagnosis
Non-allergic gastrointestinal food reactions
Lactose Intolerance
Irritable Bowel Syndrome
Carcinoid Syndrome
Giardia
sis
Celiac Sprue
Diagnosis
Immediate Reacting IgE skin Test
Epicutaneous stick with Fresh Food Extract
Sensitive and Specific
Do NOT perform for food suspected of
Anaphylaxis
In-Vitro test for allergen-specific IgE Antibodies (
RAST
)
Less sensitive than skin test
Safe alternative to skin test (
Anaphylaxis
suspected)
Open Food Challenge
Use for reintroduction of foods after 2-3 years
For foods with less serious reactions
Example:
Hives
to milk or eggs
Diet diaries
Short-term
Elimination Diet
s
Management
Milk Allergy or intolerance with GI Symptoms
Differentiate from
Infantile Colic
Colic
will resolve spontaneously after 3-4 months
Milk substitution is unnecessary
Substitute Casein Hydrolysate (Cow's Milk) Formula
Nutramigen, Pregestimil, Alimentum
Soy-based formula is not appropriate substitution
Management
Anaphylaxis
reaction history
Indefinitely avoid causative food
Epinephrine
Self-Injectors for home/school (Should have 2 pens available)
Child over age 6
Epinephrine
(1:1000) 0.3 mg SQ (
EpiPen
)
Child under age 6
Epinephrine
(1:2000) 0.15 mg SQ (Epi-Pen Jr)
Management
Reintroduction of prior food allergies
Mix with other foods
Eggs in baked products (instead of scrambled eggs)
Milk in Cheese or yogurt (instead of glass of milk)
Do not reintroduce foods with previous
Anaphylaxis
Do not re-introduce nuts, seeds or seafood if prior
Allergic Reaction
(especially if history of
Anaphylaxis
)
Management
Specific food Issues
Egg Allergy and
Vaccination
s
Indicated
Vaccine
s regardless of egg allergy severity (these
Vaccine
s contain only minute egg amounts)
Measles Mumps Rubella Vaccine
(
MMR Vaccine
)
Varicella Vaccine
Possibly indicated
Vaccine
s
Influenza Vaccine
May be given if egg
Allergic Reaction
was limited to
Urticaria
(especially if tolerates egg containing foods)
Consider monitoring for 2 hours after
Vaccination
Skin Testing
for
Influenza Vaccine
reaction is not recommended due to high
False Positive Rate
Contraindicated
Vaccine
s (if hives,
Angioedema
,
Anaphylaxis
to egg)
Rabies Vaccine
Yellow Fever Vaccine
Fish Allergy
Avoid fresh and saltwater fish
Most fish-allergic patients can tolerate canned tuna
Nut allergy (often associated with
Anaphylaxis
)
See
Palforzia
(
Peanut Allergen Powder
)
Do not eat at buffets
Avoid unlabeled candies and desserts
Avoid ice cream parlors
Milk allergy
Avoid not only cow's milk, but also sheep and goat's milk
Avoid butter or margarine containing milk
Crust
acean allergy
Avoid all crustaceans (shrimp, lobster, crab...)
Associated Conditions
Oral Allergy Syndrome
Food dependent
Exercise
induced
Anaphylaxis
(rare)
Wheat is most common associated food trigger
Anaphylaxis
occurs only if specific food trigger ingested before
Exercise
Space
Exercise
at least 6 hours after trigger food is ingested
Food-induced
Urticaria
Food allergies account for 30% of acute cases but rarely cause
Chronic Urticaria
Atopic Dermatitis
Improves when eggs, milk and peanuts are removed from diet
Associated Conditions
Conditions NOT associated with Food Allergy
Abnormal Child Behavior
Myths:
Hyperactivity,
Insomnia
, Anxiety (Shannon,1922)
"Allergic Attention
Fatigue
Syndrome" (Rowe, 1950)
Reality
No proven relationships
Attention-Deficit Disorder (ADD)
Myth:
Attention Deficit Disorder
related to dietary additives
Dietary
Salicylate
s
Artificial food colors and flavors
Feingold, 1975
Reality
Only 2% ADD Children would benefit from diet change
Reference
Lipton (1983) J Am Diet Assoc 83:132-4 [PubMed]
Sugar "Allergy"
Myth: Refined sugars aggravate behavioral problems
Suggested to provoke hyperactivity, aggressive, inappropriate behavior
Reality
Sugar does not increase activity
Milich (1986) Clin Psychol Rev 6:493-513 [PubMed]
Mahan (1988) Ann Allergy 61:453-8 [PubMed]
Sucrose has "calming effect" when c/w
Aspartame
Kruesi (1986) Annu Rev Nutr 6:113-30 [PubMed]
Bachorowski (1990) Pediatrics 86:244-53 [PubMed]
Prognosis
Transient Food Allergies
Most food allergies last only a few years
Milk, eggs, wheat or soy allergies usually resolve
Egg allergy: 70% resolve by age 5 years
Milk allergy: 85% resolve by age 5 years
Lifelong Food allergies
Foods associated with systemic
Anaphylaxis
Nuts, fish, seed allergies persist
Prevention
Recommended strategies to prevent Food Allergy
Exclusive
Breast Feeding
until 4-6 months of age
Solid food introduction by 6 months of age
Potentially allergenic foods may be introduced at this time
Strategies to avoid (not effective or unsupported)
Maternal dietary restrictions during pregnancy and
Lactation
are not recommended
Soy infant formula substitution for cow's milk infant formula is not recommended
Resources
Food Allergy and
Anaphylaxis
Network
http://www.foodallergy.org
References
Anderson (1997) Am Fam Physician 56(5): 1365-74 [PubMed]
Kurowski (2008) Am Fam Physician 77(12):1678-86 [PubMed]
Moneret-Bautrin (2005) Curr Allergy Asthma Rep 5(1):80-5 [PubMed]
Nowak-Wegrzyn (2006) Med Clin North Am 90(1):97-127 [PubMed]
Sampson (2002) N Engl J Med 346:1294-9 [PubMed]
Yawn (2012) Am Fam Physician 86(1): 43-50 [PubMed]
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