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.
