Rhinology Allergy General Flashcards
What hypothesis postulates that the increase in
allergic and atopic diseases in the world is
secondary to reductions in infectious disease as
well as cleaner environments that limit our
exposure to common allergens when we are young
and more likely to become tolerant to them rather
than allergic?
Hygiene hypothesis
What are the two phases of an allergic reaction?
Early and late responses
What is the clinical term used to refer to patients who
have a genetic predisposition toward developing an
allergic response after exposure to an antigen?
Atopy
What are the types of hypersensitivity reactions?
Type I: Immediate/anaphylactic or antibody mediated
● Type II: Cytotoxic T-cell mediated
● Type III: Immune complex mediated
● Type IV: Delayed hypersensitivity
What is another name for the hypersensitivity
reactions?
Gell and Coombs classes
Anaphylaxis is a form of what type of
hypersensitivity reaction?
Type I, immediate or antibody-mediated
What is the most important cytokine in the early
or acute phase of a type I hypersensitivity
reaction?
Histamine
What is the predominant cell type during an early
or acute phase type I hypersensitivity reaction?
Mast cells
What is the predominant cell type during the late
phase of a type I hypersensitivity reaction?
Eosinophils
In what type of hypersensitivity reaction might
you see a systemic hypersensitivity induced by an
unknown factor that results in IgG- or IgM-
mediated cytotoxic action against an antigen
located on the surface of a cell (or complement-
mediated lysis of the cell)?
Type II (cytotoxic) hypersensitivity
In what hypersensitivity reaction are immune com-
plexes formed (IgG) as a result of the presence of
drugs/bacterial products, which result in complement activation and a delayed (days) acute
inflammatory reaction?
Type III (immune complex mediated) hypersensitivity
In what hypersensitivity reaction do antigens
directly stimulate T-cell activation and cell-
mediated inflammation resulting in dermatitis,
granulomatous disease and some fungal disease?
Type IV (delayed) hypersensitivity
What three cell types are required during the
primary antigen exposure for the formation of
antigen specific IgE antibody formation?
● Mast cells
● T cells (T-helper cells type 2 [TH2] pathway)
● B Cells
After reexposure to an antigen, what is the result
of antigen-specific IgE crosslinking on mast cell
surfaces followed by release of preformed
mediators (histamine, tryptase, chymase) and syn-
thesis of newly formed mediators (leukotrienes,
prostaglandins, platelet activating factor,
interleukins, etc) that results in allergic symptoms
within minutes?
Early phase allergic response
After reexposure to an antigen, what occurs after
the release of newly generated inflammatory
mediators that cause eosinophil, basophil,
monocyte, and lymphocyte migration, infiltration,
and cell-mediated inflammation, which can take
hours (i.e., 3 to 12 hours) to occur and can last for
up to or more than 24 hours?
Late-phase allergic response
What is the definition of anaphylaxis?
A severe life-threatening generalized or systemic hyper-
sensitivity reaction that may involve urticaria, angioedema,
bronchospasm, hypotension, and shock
What are the criteria for diagnosing anaphylaxis?
● Criterion 1: Acute onset (minutes) of illness with
involvement of skin, mucosa, or both with either
respiratory compromise or hypotension
● Criterion 2: At least two of the following occurring within
minutes of an exposure to a likely allergen:
○ Involvement of skin-mucosa tissue
○ Respiratory compromise
○ Hypotension
○ Persistent gastrointestinal symptoms
● Criterion 3: Hypotension after exposure to a known
allergen for the patient
What are the two most common causes of
anaphylaxis?
● Foods
● Drug reactions
What medication, not including antibiotics, most
commonly causes drug-induced anaphylaxis?
ACE inhibitors
A patient has multiple recurrent episodes of
anaphylaxis with an unidentified cause. The
patient states his allergist asked him to have a
laboratory test in the emergency department the
next time he had an episode of angioedema in an
effort to confirm the diagnosis. What test does
the allergist want, and when should it be drawn?
Serum tryptase. Serum tryptase peaks in 30 minutes and
should be drawn within 3 hours of the start of the episode.
What percentage of patients with anaphylaxis
initially have cutaneous findings?
Greater than 90%
What is the most common condition to be
mistaken for anaphylaxis?
Vasodepressor reaction, usually triggered by trauma or
stress and manifesting as flushing, pallor, weakness,
diaphoresis, hypotension, and at times loss of conscious-
ness
What is the initial treatment of a patient with
anaphylaxis?
● Advanced cardiovascular life support (ACLS) protocol, and
secure the airway if necessary
● Elevate lower extremities in recumbent position if
possible
● Supplemental O2 (100%, 8 to 10 L by open face mask)
● Gain peripheral IV access (two large-bore IVs) → fluid
resuscitation
● First-line medications:
○ Vasopressors (i.e., intramuscular epinephrine) if hypo-
tension is not responding
○ Second-line medications
○ IV H1- or H2-antihistamine (e.g., diphenhydramine
50 mg IV)
○ Nebulized ß2-adrenergic agonist
○ Administer corticosteroids (e.g., dexamethasone 8 to
10 mg IV)
Remember, death can occur in minutes!
What dose of epinephrine should be given during
anaphylaxis to adults and children?
Intramuscular administration is preferred to subcutaneous:
1 mg/1 ml (1:1000), mid-outer thigh
● Adult: 0.3 to 0.5 mg
● Child: 0.01 mg/kg, maximum 0.5 mg
Can repeat at 5- to 15-minute intervals
Note: Autoinjectors generally have 0.3-mg doses for adults
and 0.15-mg doses for children who weigh < 25 kg.
What is the primary reason for administering an
antihistamine to patients with anaphylaxis?
Resolution of cutaneous manifestations of anaphylaxis
A patient taking what kind of class of drugs
might be refractory to the treatment of
anaphylaxis?
β-blockers
What type of anaphylaxis results in recurrence of
symptoms after the initial resolution of associated
symptoms without any additional allergen
exposure?
Biphasic anaphylaxis (23% of adults, 11% of children; generally 8 to 10 hours after initial reaction)
What is the definition of angioedema?
Significant swelling of deep dermal or subcutaneous
tissues; less often associated with pruritus and more
commonly associated with burning or pain
What is the most common cause of angioedema
presenting to emergency departments today?
ACE inhibitors
What is the cause of hereditary angioedema?
The condition is caused by high levels of activated C1 in the
bloodstream secondary to deficiency of C1 inhibitor.
What is the mechanism of inheritance of
hereditary angioedema?
Autosomal dominant
What is the treatment for hereditary angioedema?
Attacks usually spontaneously abate in 3 to 4 days. Many
patients respond to androgen derivatives, such as danazol,
that stimulate the production of C1 inhibitor and C4 but help
even at levels that do not stimulate the production of these
proteins. Purified C1 inhibitor is now starting to be used in
Europe for acute attacks or monthly preventative therapy.
Laryngeal involvement may not respond to subcutaneous
epinephrine, and a tracheostomy may be needed.
Inhalant allergens include proteins such as pollens,
animal dander, and molds. How is an inhalant
allergy classified in the United States, and based
on the World Health Organization (WHO) ARAI
(allergic rhinitis and its impact on asthma)
guidelines?
U.S. Classification
● Seasonal allergy (outdoor allergen): Seasonal occurrence,
winter/spring = tree, summer = grass, fall = mold
● Perennial allergy (indoor allergen): No consistent seasonal
pattern, dust mites, animal dander, etc
WHO ARAI Guidelines
● Intermittent allergic rhinitis: Present < 4 days/week, < 4
weeks/year
● Persistent allergic rhinitis: Present > 4 days/week, > 4
weeks/year
● Mild: Does not impact quality of life or function
● Moderate/severe: Does impact quality of life or function
During which seasons would you expect to see
seasonal allergic rhinitis in response to the
following inhalant allergens?
● Elm, birch, ash, oak, aspen, maple, box elder,
hickory, sycamore, cedar, etc.
● Bermuda grass, Johnson grass, sweet vernal
grass, Timothy grass, Orchard grass, etc.
● Ragweed, nettle, mugwort, sage, lamb’s quarter,
goosefoot, sorrel, etc.
● Winter/spring (February-May)
● Late spring/summer (April-August)
● Late summer/fall (July to first hard frost)
What are some measures to decrease exposure to
house dust mite antigen?
● Wash bedding weekly at > 130°F
● Use impermeable covers over pillows and bedding
● Use hardwood flooring or laminates instead of carpet
● Keep humidity levels at less than 45%
How long after removing a pet from a home can
it take for the amount of allergen to decrease
below clinically significant levels?
4 months
What is the definition of urticaria?
Pruritic, erythematous cutaneous elevations that blanch
with pressure
What percentage of the general population will
develop urticaria at some point in their lives?
10 to 20%
A patient with aspirin-sensitive asthma and
urticaria. In addition to NSAIDs, what chemical,
used in foods, would you recommend they avoid
as well?
Tartrazine (Yellow #5); as many as 15% of affected
individuals also react to this.
Infection with what pathogenic organism is most
commonly associated with eosinophilia and
urticaria?
Helminth infections such as Ascaris lumbricoides
What is cold urticaria, and what should patients
be warned to avoid?
Rapid swelling, erythema, and pruritus after exposure to
cold objects or weather. It affects only the areas exposed to
the cold. There have been reported deaths, secondary to
hypotension, of people who swam in cold water.
What clinical test might be used to determine
whether a patient suffers from cold (temperature)
urticaria?
Clinical history is most important. However, the ice cube
test can be used to confirm the diagnosis. Place an ice cube
on the forearm for 4 minutes, and then observe the area for
10 minutes. Symptoms should develop in 2 minutes.
Stroking of the skin with a fingernail or tongue
blade causes a wheal and flare reaction where the
skin was touched. What is the diagnosis?
Dermatographism
What form of allergy testing must be used in
patients with dermatographism?
Radioallergosorbent test (RAST) or enzyme-linked immu- nosorbent assay (ELISA)-based blood assays
What is the treatment for dermatographism?
Patients are typically treated with diphenhydramine or
hydroxyzine 25 to 50 mg daily. Use of second-generation
antihistamines works for mild symptoms. Doses needed are
typically two or three times the advised doses.
A patient has a history of developing itchy red
skin on any sun-exposed skin and intense hives
if he or she spends any significant time in the sun.
The patient does not report a similar reaction
when exposed to heat not associated with sunlight.
How is this type of reaction classified?
Solar urticaria is classified by the wavelength of light that
causes immediate hypersensitivity.
What immunoglobulin mediates most food
allergies?
IgE
