Chapter 5:
Hypersensitivity disorders
what is the prevalence of allergic rhinitis in the US?
Worldwide?
US- 8-26%w
worldwide 10-30%
at what age is
... [Show More] allergic rhinitis uncommon?
< 2 years old (especially for seasonal AR)
is AR more common in males or females in childhood?
males, but no gender disparity by adulthood
what is the mean age of onset of allergic rhinitis/
10 years old
80% of cases developing before 20 years of age.
what percent of AR is seasonal? perennial? mixed?
20% seasonal
40% perennial
40% mixed
what are risk factors/changes that may have contributed to the rise in allergic disease?
-increased exposure to perennial indoor allergens
-decreased exposure to infections in childhood (the hygiene hypothesis) related to eradication of helminths and malaria and introduction of immunization and increased abx use, as well as less exposure to farm animals.
compared to general population, individuals with AR ....
rate the health significantly lower
difficulty initiating and maintaining sleep
decreased productivity at work
AR pathophysiology?
results from sensitization to aeroallergens (dust mite, pet, pollen).
epithelial cell release of PGE2 and TSLP polarize toward a Th2 response.
allergens cross link specific IgE receptors on FCeRI on mast cells, which lead to activation and degranulation.
what are the pre-formed mediators in mast cells?
histamine
tryptase
bradykinin
what are the newly formed mediators in mast cells?
PGD2
LTC4, LTD4, LTE4
name the symptom that goes with the specific mediators?
Histamine --
PGD2 --
Leukotrienes --
Kinins --
Histamine -- itch, sneeze, rhinorrhea
PGD2 --nasal congestion
Leukotrienes -- nasal congestion
Kinins -- nasal congestion
AD
describe late allergic response?
begins within 4-8 hours and can last 24 hours
what 2 signals induce IgE production?
1) Th2 lymphocyte secreted IL-4 and IL-13
2) CD40-CD40L B and T cell lymphocyte interaction
AR may be associated with lower airway abnormalities, such as ____________, even in the absence of asthma
basement membrane thickening
FeNO is a sensitive marker of inflammation that is increased in ______ and decreased in ____?
AR
sinusitis
Chronic inflammatory changes lower the threshold of mucosal responsiveness to _____?
irritant and allergic stimuli.
what is priming?
progressively lower doses of allergen are needed to trigger subsequent symptoms
residence in a geographic location is required for ____ for sensitization to take place?
1 year
what are physical signs of AR?
allergic shiners
transverse nasal crease
Dennie-morgan lines
pale nasal mucosa
turbinate hypertrophy
mouth breathing
cobblestoning of oropharynx
SPT are more ____ that ss IgE testing?
sensitive
but less specific
how should you classify AR?
severity (mild, moderate or severe)
frequency (intermittent vs persistent)
AD
describe treatment options of AR?
Most effective tx: -- intranasal steroid
--intranasal antihistamine: first line for seasonal and intermittent AR.
--Oral antihistamines
--Antileukotrienes
--decongestants
--allergy shots
onset of action of intranasal steroids?
side effects?
cause vasoconstriction, reduction of mucosal edema
inihibition of mast cells and cytokines.
also help ocular symptoms.
Onset of action -- few hours, but max effect after 2-4 weeks
side effects: dryness, burning, stinging, epistaxis
onset of action of intranasal antihistamines?
15-30 min
given on demand.
also help with eye symptoms.
side effects: bitter taste and somnolence (prob not much of an issue)
FDA approved first OTC intranasal antihistamine (Astepro)
0.15% strength approved in children > 6.
are oral antihistamines as good as intranasal antihistamines
no
side effects of oral antihistamines:
1st gen (hydroxyzine, doxepin) cross BBB and cause sedation
they also bind muscarining receptors and can cause dry mouth, urinary retention, hypotension, etc.
recent studies suggest increased risk of dementia
what is the black box warning on singulair?
neuropsychiatric events like depression, suicidality and insomnia
when should you give singulair for AR?
if they cannot take alternative meds or are not responding.
what ages is Singulair approved for?
FOR AR: > 1 years old
for asthma: > 6 years old.
what is the dosing for singulair?
6-15 years old - 5 mg.
> 15 years old - 10 mg
what decongestants are good for AR?
pseudoephedrine (alpha-adrenergic agonist), effective at relieving nasal congestion.
phenylephrine - ineffective.
who should you be cause about using decongestants in?
< 6 years old,
elderly
pregnant (1st trimester)
When should you recommend intranasal decongestants?
short term or intermittent therapy. [Show Less]