Food Allergy and Intolerance Flashcards
inappropriate immunologic response to antigens in food
immediate (IgE) Food Allergy
prevalence of Food Allergy
10-11% of the US population
onset of food allergy
any age, usually in childhood
15% manifest for the first time as adults
risk factors for food allergy
Comorbid atopy
eczema
asthma
allergic rhinitis
other allergic disorders
food allergy is an inappropriate activation of the immune system, mediated by what immunoglobulin
IgE
manifestations of food allergy
- present after even a tiny exposure to the allergen (ingestion, topical, inhaled)
- very rapid onset - mins-hrs (< 2 hours) - Unpredictable - may vary from one exposure to the next
- Severity - ranges from relatively mild to extremely severe or life-threatening
associated with problems digesting or metabolizing food
Food Intolerance
prevalence of Food Intolerance
15-20% of the US population, if not more
onset of Food Intolerance
at any age, including adulthood
risk factors of food intolerance
Often have functional gastrointestinal disorders (IBS, functional dyspepsia, others)
food intolerance - if Ig present, more likely to be ___
non-IgE, including IgG
manifestations of food intolerance
- Usually present after exposure to the food, with severity correlating with dose of food ingested
- manifest up to 72 hr after exposure - Symptoms focus around the GI tract
- Typically predictable - similar presentations each time, depending on dose of food
- Severity - may be uncomfortable, but usually not life-threatening
most common problem foods for food allergies
usually proteins
Typically no difference in varieties that are organic, not treated with antibiotics
MC allergenic foods in the US
Peanuts, tree nuts, and fish/shellfish
Other common allergens - wheat, eggs, milk, soybeans, sesame
Over ___ possible food and additive allergens
160
some common food intolerances
problem foods vary widely
1. Lactose, fructose, gluten, caffeine
2. General carbohydrate intolerance - usually secondary to high-FODMAP foods
9 most common allergens must be listed on food labels if present
Peanuts, tree nuts, fish, shellfish, wheat, eggs, milk, soybeans, sesame
what is Not required to identify if product is at risk for environmental contamination
food labels
what were the old guidelines (pre-2008) of allergen exposure.
- avoid exposure to allergens in early life
- Based off theory that due to low secretory IgA in infants, less antigen would be bound (more absorbed) and therefore could trigger a greater immunogenic response
what are the newer guidelines of allergen exposure
no convincing evidence to delay allergen exposure
1. Data suggested delayed exposure actually might increase risk of food allergy
2. May consider delaying/avoiding in select children with high risk for food allergy
- Family history of food allergy
- Strong presence of atopic/allergic disorders
- May also consider hypoallergenic infant formulas, modifying mother’s diet
ways for childhood allergen exposure
- early indirect exposure
- Having mother eat allergenic foods while pregnant
- Consuming allergenic foods while breastfeeding - Introduction of allergens for direct consumption
- Foods made with allergens
- Mix-in liquids or powders
presentation of immediate (IgE) food allergy
present from a few minutes to a few hours (usually 2 or less) after exposure to the allergenic food
- Derm - pruritus, flushing, urticaria/angioedema, diaphoresis
- Eyes - conjunctival injection, lacrimation, periorbital edema, pruritus
- Nose - sneezing, rhinorrhea, nasal congestion
- Mouth - oral pruritus, metallic taste
- Upper Airway - hoarseness, stridor, sense of choking, laryngeal edema
- Lower Airway - dyspnea, tachypnea, wheezing, cough, cyanosis
- CV - tachycardia, bradycardia (if severe), arrhythmias, hypotension, cardiac arrest
- GI - N/V/D, abdominal cramping, bloating
- Neuro - sense of impending doom, panic, syncope, dizziness, seizures
clinical presentation common in children for food intolerences
trend towards cutaneous and GI symptoms
clinical presentation common in adults in Immediate (IgE) Food Allergy
trend towards respiratory and CV symptoms
management for acute food allergy
limiting inflammatory response
1. Administration of EPI ASAP
2. Additional therapeutics - steroids, antihistamines, beta-agonists, other supportive care
management for chronic food allergy
focus on avoiding allergenic food exposures
Oral Allergy Syndrome aka ___
Pollen-Allergy Food Syndrome
what is the MC form of food allergy in adults
Oral Allergy Syndrome
Allergens in some foods have similar molecular structure to allergenic pollen proteins
These allergens are heat-labile and acid-labile
Much milder presentation overall
pts with Oral Allergy Syndrome usually report a hx of ?
seasonal allergies, pollen sensitivity
Initial sensitization is typically to pollen, and patients then experience IgE-mediated cross-reactivity
Localized, mild immune (IgE) response
Oral Allergy Syndrome
s/s of Oral Allergy Syndrome
- present usually within a few minutes after exposure to the allergenic food
- Mouth - oral pruritus, swelling of oral structures
- Upper Airway - hoarseness, laryngeal edema, mild stridor or sense of airway narrowing
Oral Allergy Syndrome usually presents after exposure to what?
raw fruits and vegetables
Do not have symptoms with same foods if cooked
management for Oral Allergy Syndrome
- Acute Management - usually self-limiting
- Antihistamines
- Monitor - Chronic Management - avoiding allergenic foods
- Antihistamines and other methods to control underlying allergic condition
- Eating cooked versions of foods - May for work-up of more serious allergic disorder if…
- Symptoms are present after tree nut or peanut exposure
- Systemic symptoms are present
disorder characterized by inability to digest lactose, a milk sugar, due to deficiency of the enzyme lactase
Lactose Intolerance
what tolerance is actually considered normal for adult mammals
Lactose Intolerance
what is the Most common enzyme deficiency - >50% of adults worldwide are deficient
Lactose Intolerance
at what age does natural levels of lactase often decline
5 y/o
what is the ethnic ties with lactose intolerance
Northern European descent - most likely to tolerate lactose well
African, Asian, Mediterranean, Native American - most likely to have lactase deficiency
s/s of Lactose Intolerance
- GI - abdominal pain, bloating, flatulence, borborygmi, nausea, diarrhea hours-days after ingestion of lactose-containing food or beverage
- abd pain - cramp-like, localized to periumbilical area or RLQ/LLQ
- Children - more likely to have predominant diarrhea; may see bulky, frothy, watery stool - Severity of symptoms varies depending on amount of lactose consumed, presence of other GI comorbidities, patient sensitivity to symptoms
how to diagnose Lactose Intolerance
- clinically; can trial a lactose-free diet to see if symptoms improve
- Stool Studies - increased stool osmotic gap and decreased stool pH due to undigested lactose that becomes fermented by gut bacteria
- Hydrogen Breath Test - patient consumes solution containing lactose and serial breath samples are measured for hydrogen content
- Small Bowel Biopsy - can be performed during endoscopy to measure presence of lactase enzyme
tx for lactose intolerance
focuses on minimization of lactose in diet
1. Dietary Lactose Restriction - equivalent of 2 cups of milk/day or less
- Increasing numbers of products with less lactose content
2. Calcium / Vitamin D Supplementation
- To avoid nutritional deficiency
3. Lactase Enzyme Supplementation - may try, but variable results
protein found in many cereal grains
Wheat, rye, barley, triticale, malt, brewer’s yeast, wheat products (spelt, semolina, farina, etc.)
gluten
Non-Celiac Gluten Intolerance is how common? (%)
13%
Gluten-Sensitive Enteropathy (Celiac Disease) is how common?
1% of US
what intolerance
Historically found predominantly in patients of European descent
Increasing prevalence in multiple ethnic and racial groups
North Africa, Middle East, India, Northern China
gluten intolerance
s/s of gluten intolerance and celiac disease
- GI - abd pain, bloating, flatulence, borborygmi, nausea, diarrhea hrs-days after ingestion
- Diarrhea - bulky, foul-smelling, floating stools due to steatorrhea
- Malabsorption - wt loss, anemia, nutritional deficiencies (B vitamins, D, calcium)
— MC with Celiac Disease - Oral - atrophic glossitis, angular cheilitis
- Skin - itchy papules (dermatitis herpetiformis)
- Neuro - headache, peripheral neuropathy, epilepsy
- Psych - depression, anxiety
- Heme - iron deficiency anemia, hyposplenism
- MSK - osteomalacia, osteopenia, increased fracture risk
how to diagnose Gluten Intolerance and Celiac Disease
can trial gluten-free diet to see if symptoms improve
1. Gluten Intolerance - dx of exclusion (no + serum or biopsy tests)
2. Serum Antibody Assay - serum antibody panel may be positive in patients with celiac disease
- advised to keep gluten in diet until panel is performed
3. Small Bowel Biopsy - can be performed during endoscopy to demonstrate atrophy of intestinal mucosa in patients with celiac disease
tx for Gluten Intolerance and Celiac Disease
- Dietary Counseling
- Consider dietician consult or social services
- Re-challenge with gluten not recommended - Repeat Testing - Monitor serum celiac-related antibodies for response to therapy
- Controversial as to whether repeat small bowel biopsy
- Atrophy of intestine does tend to improve the longer a patient avoids gluten - Supportive Care - pneumococcal vaccination, repletion of nutritional deficiencies
- Gluten Enzyme Supplementation - may try, but variable results
- Not widely recommended, esp with celiac disease
focuses on elimination of gluten from the diet
