Allergies Flashcards

1
Q

What percent of kids are affected by food allergies? What type of mediated rxns?

A
  • 6-8%

- IgE (anaphylaxis) or non-IgE mediated rxns

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2
Q

IgE mediated rxns characteristics?

A
  • typically rapid in onset (occur w/in minutes)
  • skin
  • GI tract
  • respiratory tract
  • anaphylaxis
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3
Q

8 most common sources of IgE mediated rxns (90%)

A
  • cows milk
  • eggs
  • soybean
  • wheat
  • peanuts
  • tree nuts
  • fish
  • shellfish
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4
Q

Which of the 8 most common sources of IgE mediated rxns usually (80%) resolve by age 5?

A
  • cow’s milk
  • eggs
  • soybean
  • wheat
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5
Q

Which of these common sources of allergies are usually lifelong?

A
  • peanuts
  • tree nuts
  • fish
  • shellfish
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6
Q

Characteristics of a non-IgE mediated rxn?

A
  • occurs hours to days after exposure
  • typically in infants
  • can present as chronic skin conditions or most commonly manifests as GI sxs:
    proctitis/proctocolitis
    enteropathy
    enterocolitis
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7
Q

Sxs of food induced allergic rxn (IgE and non-IgE mediated)?

A
  • cutaneous: erythema, pruritus, urticaria, angioedema
  • ocular: pruritus, conjunctival erythema, tearing, periorbital edema
  • upper respiratory: nasal congestion, pruritus, rhinorrhea, sneezing, laryngeal edema, hoarseness, dry cough
  • lower respiratory: cough, chest tightness, dyspnea, wheezing, intercostal retractions
  • GI oral: angioedema of lips, tongue, or palate, oral pruritus, tongue swelling
  • lower GI: nausea, colicky abd pain, reflux, vomiting, diarrhea
  • CV: tachycardia (occasionally bradbradia cardia in anaphylaxis), hypotension, dizziness, fainting, LOC
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8
Q

Dx of food induced allergies?

A
  • Hx
  • physical
  • skin prick test, allergen specific serum IgE, oral food challenge
  • pts with large wheals from skin prick test or with high serum specific IgE are likely to have food allergy
  • parent and pt reports of food allergy should be confirmed with testing as mult studies demonstrate 50-90% of presumed food allergies are not allergies
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9
Q

Tx of food induced allergies?

A
  • avoidance

- epi-pen for tx for anaphylaxis

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10
Q

What sxs can be assoc with food allergies?

A
  • atopic dermatitis

- acute urticaria

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11
Q

Relationship b/t atopic dermatitis (eczema) and food allergies?

A
  • food allergy has been reported in up to 35% of pts referred to an allergist or derm for atopic dermatitis
  • consider eval in infants and children with moderate to severe atopic dermatitis or if there is a hx of exacerbation when eating specific foods
  • if food allergy is dx, the atopic dermatitis often improves after dietary elimination of that food
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12
Q

Relationship b/t acute and chronic urticaria with food allergies?

A
  • the causes of acute urticaria vary and include infection, drug rxn, and food allergy
  • acute urticaria is common sx present with food allergy
  • in contrast, chronic urticaria is rarely related to food allergy
  • food allergy testing is rarely indicated for chronic urticaria since most cases are idiopathic
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13
Q

What nasopharyngeal sxs occur with food allergies?

A
  • acute rhinitis (typically assoc with other orpharyngeal sxs such as pruritus of throat and angioedema)
  • chronic rhinitis is NOT a manifestation of food allergy
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14
Q

Most appropriate test in initial assessment of food allergy? Test results?

A
  • serum specific IgE testing or skin prick testing
  • a positive rxn is a wheal at least 3 mm greater than negative control
  • neg predictive value is greater than 95% while the positive predictive value is less than 50%, therefore there are many false positive results
  • antihistamines should be d/c prior to testing
  • testing can’t be performed on skin with extensive eczema/rash or in pts with dermatographia
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15
Q

What is impt to remember about serum specific IgE testing?

A
  • detection of serum IgE to specific allergens
  • all positive and neg tests (skin and serum tests) need to be correlated with pts clinical hx
  • a + test alone doesn’t make the dx of clinical food allergy (evidence of sensitization: immunological response)
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16
Q

Gold std for dx of food allergy?

A
  • a double blind, placebo controlled food challenge. Open challenges are generally used in most clinical settings
  • pts may benefit from oral food challenge if they have borderline test results or if false + or - is suspected based on clinical hx
  • may prevent unjustified food elimination from diet
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17
Q

Oral food challenge process?

A
  • pt given gradually increasing amt of suspected food allergen over a time period of hours to a day
  • process requires close medical supervision
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18
Q

Atopy patch tests use?

A
  • currently used to d delayed hypersensitivity T cell mediated rxns such as contact dermatitis
  • atopy patch testing for IgE mediated food allergy isn’t recommended
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19
Q

What are variables in the skin tests and specific IgE tests?

A
  • each allergen may have diff normal IgE level and wheal diameter
  • also dependent on age of child
  • cutoff value is the concentration of specific IgE for particular food allergen that is 90% predictive of clinical rxn to food
  • increasing levels of specific IgE and wheal response to SPT correlate with allergy but don’t predict severity of rxn
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20
Q

Why should food be continued on a regular basis if positive IgE results with no rxn while consuming food?

A
  • because testing indicates that the child is sensitized to the allergen, a prolonged absence of the food from the diet could lead to clinical sxs upon re-exposure
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21
Q

Tx of food allergies?

A
  • children should be instructed not to share or trade food with others and to notify adults if they eat something that may contain the food to which they are allergic
  • epi-pen auto injector (should be given IM in thigh) 0.15 mg of 1:1000 epi for 15-30 kg (33-66 lbs), and 0.3 mg of 1:1000 epi for anyone over 30 kg
22
Q

What is pollen-food allergy syndrome (PFAS) or oral allergy syndrome?

A
  • IgE-mediated rxn that affects oropharynx
  • occur from cross-reactivity b/t proteins present in pollens and those in fruits and veggies
  • pts develop tingling and itching of lips, tongue, and palate when eating certain raw fruits and veggies
  • systemic signs are very rate
  • sxs don’t occur when fruit or veggie is cooked
  • syndrome affects up to 50% of adults with allergic rhinitis secondary to pollens
23
Q

What fruits and veggies have a x-reactivity with birch pollen allergy?

A
  • apples, plums, peaches, nectarines, cherries, almonds
24
Q

What fruits have a x-reactivity with ragweed pollen?

A
  • melons, bananas, and tomatoes
25
Q

What fruits have a x-reactivity with grass pollen allergy?

A
  • melons and kiwi fruit
26
Q

How do you dx PFAS?

A
  • confirmed through skin prick testing to fresh foods and pollen and also with oral food challenges
  • oral challenges are rarely necessary
27
Q

Tx of PFAS?

A
  • sxs can sometimes be controlled with antihistamines
  • pts should avoid consumption of raw food product that produced sxs: may continue to eat specific food if it is cooked
  • any pt who has hx of systemic sxs should strictly avoid the foods in all forms and carry an epi auto-injector
28
Q

Who is more at a higher risk for fatal food-induced anaphylaxis? young kids or teens?

A
  • teens
  • dose provoking sxs in peanut-allergic pts decreases with age, which may in part contribute to the difference in risk
  • studies have shown that adolescents have poor understanding of when food allergy rxns are severe and wehn epi is indicated
29
Q

How common is accidental exposure to peanuts and tree nuts?

A
  • high as 48%

- 54% of adolescents admit to purposefully eating potentially unsafe food

30
Q

Which food allergy is more common in adults than children?

A
  • shellfish
31
Q

Most common food allergies in children?

A
  • milk
  • egg
  • peanut (second most common food allergy in adults but is still more common in children - affects 0.8% of young kids - 0-5 yrs)
32
Q

Most common food allergies in adults?

A
  • shellfish
  • peanut
  • tree nut
  • allergies to tree nuts and fruits are more prevalent among adolescents and adults than children
33
Q

Epidemiology of allergic rhinitis?

A
  • peak prevalence: 14-25 yrs
  • 80% develop sxs befpre age 20
  • 10-30% of pop affected
  • 30-50 mill Americans affected
  • loss of 3.5 million work days and 2 million school days
  • cost more than 15 bill annually
34
Q

Sxs of allergic rhinitis?

A
  • sneezing
  • rhinorrhea
  • nasal congestion
  • itching of eyes, nose, palate, and ear canals
  • postnasal drip, cough
  • irritability
  • fatigue (not just from meds)
35
Q

How can AR have a significant impact on quality of life and cognitive fxn?

A
  • sleep disordered breathing
  • fatigue
  • general malaise
  • cognitive and psych issues in kids: ADHD, lower exam scores in peak pollen season, poor concentration, impaired athletic performance and low self esteem
36
Q

What diseases are assoc with allergic rhinitis?

A
  • otitis media and eustachian tube dysfxn
  • sinusitis
  • asthma
  • sleep related breathing disorders
37
Q

DDx of allergic rhinitis?

A
  • viral URI
  • chronic sinusitis
  • adenoidal hypertrophy
  • septal deviation
  • turbinate hypertrophy
  • fbs
  • choanal atresia
  • nasal polyps
  • immunodeficiencies
  • CSF leak
  • tumors
38
Q

Physical presentation of AR?

A
  • allergic salute: transverse crease across nasal bridge
  • allergic shiner: dark swollen, infra-orbital tissue
  • Dennie morgan lines: infra-orbital creases due to edema and thickening of skin
  • conjunctival chemosis
  • cobblestoning in throat and under eyelid
39
Q

AR - manifestations in nose?

A
  • common allergic rxn that causes inflammation in lining of nose
  • inflamed nasal lining (appears pale, boggy blue)
  • postnasal drip
  • clear nasal d/c
40
Q

Dx or AR?

A
  • suggestive hx
  • supportive exam
  • identify specific IgE
41
Q

Diff b/t sensitization and allergy?

A
  • both skin testing and serum IgE testing detect sensitization - presence of specific IgE to an allergen
  • Allergy is a clinical syndrome with sxs combined with evidence of sensitization (Positive skin or serum test)
42
Q

Tx of AR?

A
  • enviro control
  • pharm:
    antihistamines, decongestants, nasal steroids, anticholinergics, mast cell stabilizers, ocular meds, leukotriene modifiers
  • immunotherapy
43
Q

Classification of AR?

A
  • intermittent mild: less than 4 days a week, or less than 4 weeks, mild - normal sleep and daily activities, normal school and work, and no troublesome sxs
  • intermittent mod-severe
  • persistent mild
  • persistent moderate-severe: more than 4 days/week, and more than 4 weeks, will have one or more of the following: abnormal sleep, impairment of daily activities, sports, leisure, problems caused at work and school, troublesome sx
44
Q

Approach to kids under 2 with AR?

A
  • uncommon

- in all pts avoidance therapy is most effective 1st line therapy

45
Q

Meds approach for kids younger than 2?

A
  • no first gen antihistamines (worried about respiratory depression and death)
  • cromolyn nasal spray
  • 2nd gen antihistamine: ceterizine, fexofenadine (kids greater than 6 mo)
  • intranasal glucocorticoids if severe sxs and no response to above therapies (too much systemic absorption in this young of kids)
46
Q

Med approach for kids older than 2 with mild or episodic sxs?

A
  • cetirizine, loratidine, or fexofenidine: 2-5 hrs prior to exposure
  • or intranasal topical antihistamine (azelastine: older than 5, and olopatidine for kids older than 12)
  • intranasal glucocorticoid: more effective antihistamines
  • or intranasal cromolyn 30 min prior to exposure
47
Q

Med management for kids older than 2 with persistent or severe sxs?

A
  1. intranasal glucocorticoid
  2. topical nasal antihistamine
  3. oral antihistamine
  4. decongestant
    - start with 1st med and add on in this order if needed for persistent sxs
48
Q

Intranasal glucorticoids for kids?

A
  • mometasone (nasonex): kids 2 and older
  • fluticasone furoate (veramyst): kids 2 and older
  • fluticasone propionate (flonase) for kids 4 and older
49
Q

Topical nasal antihistamines in kids?

A
  • Azelastine (Astelin) for kids older than 5
  • Olopatidine (patanase) for kids older than 12
  • combo azelastine and fluticasone (dymista) older than 12
50
Q

Meds for AR with allergic conjunctivitis?

A
  • intranasal glucocorticoid + topical ophthalmic antihistamine drops
  • combo less drying than oral antihistamines
51
Q

Meds for AR with asthma? BBW?

A
  • leukotriene modifier (inhibits mast cell degranulation):
    monteleukast (singulair)
    approved for use in kids as young as 6 months
  • SEs: are depression and suicidal ideations in adults (BBW )
  • more common in kids: hyperactive and emotional, anxiousness