CM- Sneezing, Wheezing, Allergies Flashcards
What is the total prevalence of allergic rhinitis?
How does the prevalence change with age?
How many years is a person exposed to an offending allergen to get rhinitis?
20% and decreases with advancing age
Most ppl develop symptoms by 20 and require 2 years of exposure to the offending allergen
What causes allergic rhinitis?
What happens in the early phase and late phase?
Allergen deposits in the nasal cavity where it interacts with mast cells and basophils to crosslink IgE to degranulate the cells
Early phase (15-20 minutes post exposure):
itching, sneezing, runny nose, congestion
-histamine, kinins, PGD2, LTBCDE4
Late phase (4-6 hours)
- eosinophils, basophils, neutrophils, same reactive substances as early phase
- TH2 lymphocytes play a role as a source of IL4 (IgE production) IL5 (eosinophil activation)
- ICAM, VCAM upregulate to direct inflammatory cells to the site
What symptoms are associated with allergic rhinitis?
- paroxysmal sneezing, itching, rhinorrhea (clear)
- seasonality
- eye or chest symptoms
What symptoms are associated with non-allergic rhinitis?
- congestion (no sneezing/itching)
- postnasal drip
- minimal eye irritation
What are “red flag” symptoms of rhinitis?
- unilateral -polyps/deviated septum
- bleeding
- pain
Upon physical examination, how do the turbinates differ with allergic rhinitis and non-allergic rhinitis?
How are they similar?
Allergic:
pale, blue and edematous
Non-allergic:
erythematous and edematous
Similar in that they are both edematous
What 3 areas of the body should be the focus for physical examination of suspected rhinitis?
Eyes, ears and upper airway
What are the classic features seen in the eyes for someone with rhinitis?
- conjunctivitis
- periorbital cyanosis (“allergic shiners”)- sign of venous congestion in addition to nasal obstruction
- Denny Morgan lines (extra skin creases under medial aspect of the eye)
Nasal polyps can cause rhinitis symptoms independent of allergies. What clinical feature should make you suspicious of nasal polyps?
Loss of smell and taste
What are the most common seasonal allergies?
What are the most common perennial allergies?
Seasonal :
Pollen (mountain cedar, tree, grass, weed)
Perennial:
dust mites, pets, cockroaches, mold, latex
What is vasomotor rhinitis?
When does it present? How does it differ from allergic rhinitis?
What exacerbates it?
It is perennial and is characterized by:
- nasal obstruction
- rhinorrhea
- post-nasal drip
LITTLE TO NO ITCHING**
It is exacerbated by irritants (strong odors) and weather changes
What is rhinitis medicamentosa?
Prolonged (several weeks) use of topical decongestant sprays lead to rebound nasal congestion and tachyphylaxis (dependency on the medication)
In addition to nasal sprays, what other medications can cause rhinitis?
oral contraceptives
antihypertensives
conjugated estrogen
What are the main differential diagnoses for allergic rhinitis?
- Allergic- seasonal/perennial
- endocrine/hormonal - pregnancy
- infectious- URI, sinusitis
- medication induced
- non-allergic - vasomotor
What are the steps to diagnosis of allergic rhinitis?
- get a careful history! (much more important than the physical exam)
- nasal smear with eosinophilia is suggestive
- allergy skin testing is most accurate and preferred method but must be done by a specialist
- RAST (Immunocap) testing- detects specific IgE in vitro
What is RAST?
What are the benefits?
It detects in vitro specific IgE
RAST to dust mites and pets is a cost effective way to see if that is the cause of the allergic rhinitis before avoidance measures need to be taken
What is the most preferred and most accurate method for diagnosing allergic rhinitis? What is the drawback?
Allergic skin testing- the drawback is that it is limited to specialists
What type of allergic rhinitis usually can be diagnosed by history alone?
seasonal allergies
When would it not be necessary to perform testing for specific IgE?
If it is allergic or vasomotor rhinitis that is responding to conventional treatment.
What is the 3 tiered approach for rhinitis therapy?
- Allergen avoidance
- Pharmacotherapy (antihistamines, decongestants, anticholinergics, glucocorticoids, cromolyn LT modifiers)
- Immunotherapy
What are the 4 main categories of drugs for rhinitis therapy?
- antihistamines
- anti-inflammatory- glucocorticoids, cromolyn, LT modifiers
- decongestants
- anticholinergics
When is immunotherapy used?
How does it work?
How long does it last?
It is used when the patient does not respond to pharmacologic treatment.
It is the only therapy to reduce allergic sensitivity.
Weekly doses of allergen extracts are given in the physicians office for 3-6 months to build up tolerance. You can also do a rapid one day desensitization but it requires monthly maintenance doses.
Effects last 3-5 years and there is partial tolerance