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Source: May JR, Smith PH. Allergic
Rhinitis. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey
LM, eds. Pharmacotherapy: A Pathophysiologic
Approach. 8th ed. http://accesspharmacy.com/content.aspx?aid=7998284.
Accessed June 23, 2012.
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- Inflammation of nasal passages caused by allergic reaction
to airborne substances.
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- Seasonal: Occurs in response to specific allergens (pollen
from trees, grasses, and weeds) present at predictable times of
year (spring and/or fall blooming seasons).
- Perennial: Occurs year-round in response to nonseasonal allergens
(e.g., dust mites, animal dander, and molds).
- Many patients have both types, with symptoms year-round and
seasonal exacerbations.
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- Airborne allergens inhaled into nose processed by lymphocytes,
producing immunoglobulin E (IgE).
- On nasal reexposure,
IgE bound to mast cells interacts with airborne allergens, triggering
release of inflammatory mediators.
- Within seconds to minutes, rapid release of mediators (histamine,
leukotrienes, prostaglandin, tryptase, kinins) causes:
- Vasodilation
- Increased vascular permeability
- Nasal secretions
- Histamine produces:
- Rhinorrhea
- Itching
- Sneezing
- Nasal obstruction
- Late-phase reaction 4–8 hours after initial exposure
may cause chronic symptoms, including nasal congestion.
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- Affects about 50 million Americans of all ages.
- Prevalence of seasonal rhinitis between 1–40%;
perennial rhinitis prevalence ranges from 1–13%.
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- Allergen avoidance important to prevent episodes but often
difficult to accomplish.
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- Genetics
- Allergen exposure
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- Clear rhinorrhea; sneezing; nasal congestion; postnasal
drip (occasionally with cough or hoarseness); allergic conjunctivitis;
and pruritic eyes, ears, or nose.
- May be loss of smell or taste, with sinusitis or polyps underlying
cause in many cases.
- Untreated rhinitis may lead to:
- Insomnia
- Malaise
- Fatigue
- Poor work or school performance
- Complications include recurrent and chronic sinusitis and
epistaxis.
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Means of Confirmation
and Diagnosis
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- Medical history for:
- Description of symptoms
- Environmental factors and exposures
- Results of previous therapy
- Use of medications
- Previous nasal injury or surgery
- Family history
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- Radioallergosorbent test (RAST) to detect IgE antibodies
in blood specific for given antigen.
- Peripheral blood eosinophil count may be elevated but is nonspecific
finding.
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Diagnostic Procedures
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- Percutaneous allergy testing can help determine whether
rhinitis caused by immune response to allergens.
- Microscopic examination of nasal scrapings typically reveals
numerous eosinophils.
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Differential
Diagnosis
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- Viral rhinitis (common cold)
- Viral conjunctivitis
- Vasomotor rhinitis
- Acute or chronic sinusitis
- Rhinitis medicamentosa
- Nasal polyposis
- Foreign body
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- Minimize or prevent symptoms with minimal side effects
and reasonable medication expense.
- Maintain normal lifestyle, including participation in outdoor
activities and interaction with pets.
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- Figure 1: Treatment algorithm for allergic rhinitis
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- Allergen avoidance
- Reduce household mold
growth by keeping humidity below 50% and removing obvious
growth with bleach or disinfectant.
- Remove pets that ...