ALLERGIC RHINITIS
DEFINITION:
An inflammatory disorder of the nasal mucosa initiated by an IgE-mediated
hypersensitivity.
EPIDEMIOLOGY:
- incidence: most common chronic disease of the respiratory
tract 10% of children and 20% of adolescents and young adults
- age of onset:
- risk factors:
- associations:
- an allergic triad
- 50-80% of patients with atopic dermatitis will go on to
develop asthma and/or allergic rhinitis
PATHOGENESIS:
- allergy is the manifestation of a hypersensitive reaction
to the presentation of an allergen due to the propensity of
the affected individual to develop a sustained IgE response
following antigenic stimulation
- the distinguishing feature of the allergic individual is
the propensity to develop a sustained IgE response
- there are several types of allergies based upon where the
hypersensitive reaction occurs:
- Nasal Mucosa - Allergic Rhinitis
- Skin - Hives (Urticaria), Atopic Dermatitis
- Respiratory Tract - Allergic Asthma
- Systemic - Anaphylaxis
- allergens are compounds capable of inducing human IgE
antibody formation ("sensitization")
3. IgE
- IgE is a Homocytotropic Antibody: an antibody capable of
interacting with target cells such that these cells release
mediators on contact with specific antigens
- the IgE receptor consists of an externally located alpha
chain that binds the IgE and is noncovalently associated with
a beta chain and two gamma chains
- there are two categories of IgE receptors dependent upon
the type of cells targetted and the type of mediators released
from these cells:
- target cells - mast cells, basophils
- affinity - high affinity for IgE
- mediators - histamine, ECF-A, leukotrienes,
bradykinins, prostaglandins, PAF, anaphylatoxins
2. Type 2
- target cells - lymphocytes, platelets, eosinophils,
monocytes-macrophages
- affininty - low affinity for IgE
- mediators - chemotaxic factors, IgE binding factors (T
cells), mitogens (B cells), inflammatory mediators
2. Allergic Rhinitis
- an allergy specific to the nasal mucosal in susceptible
individuals
2. Allergens
- allergen present in the environment year round
- animal danders (the saliva and urine of dogs, cats,
rodents, horses), house dust (mite feces), molds, feathers,
cockroaches
2. Seasonal (Hay Fever)
- early spring - tree pollens
- early summer - grass pollens
- early fall - weed pollens (i.e., ragweed)
3. IgE
- within the lymphoid tissue of the nasal mucosa a Type 1
homocytotropic antibody response occurs
- there are an increased number of mast cells and
basophils in the nasal mucosa
- mediator responses
- increased permeability of the nasal mucosa allowing
for an amplification of the allergic reaction
- stimulates itch receptors
- decreases the threshold for sneezing
- increased cholinergic predominance results in vascular
vasodilation & hypersecretion of mucous
- chemotaxis of cells: eosinphils, neutrophils, and
mononuclear cells
CLINICAL FEATURES:
2. Precipitation/Palliation
- identify allergens
- effect of avoidence and previous medications
3. Quality
4. Radiation
- identify other atopic conditions - hives, atopic
dermatitis, allergic asthma, anaphylactic reactions
5. Severity
- does rhinitis interfere with work or school performance or
play
6. Associated Symptoms
- noisy or oronasal breathing, nasal voice, snoring, anosmia,
hyposmia, repeated throat clearing, chronic cough
2. Symptoms
- paroxysms of sneezing, nasal congestion, clear and profuse
rhinorrhea, pruritis of the nose, palate, pharynx, and middle
ear
2. Other Mucous Membrane Manifestations
- conjunctival irritation, itching, erythema, & tearing
2. Ears
- feeling of fullness in ears with popping
3. Sinuses
- pressure and/or pain over cheeks, forehead, or behind
eyes
3. Systematic Manifestations
- malaise, weakness, fatigue
3. Signs
- allergic shiners - dark circles under eyes suggestive of
venous congestion and stasis
- transverse wrinkle
- mouth breathing
- allergic mannerisms
- wrinkling of nose (rabbit nose), allergic salute
2. Otoscope or Nasal Speculum
- clear nasal discharge
- edematous pale/blue nasal mucosa
- epistaxis in Kisselbach's area
- broadening of body dorsum (due to persistent nasal
obstruction)
- rule out:
- choanal atresia
- foreign body, mass, or polyp
- nasal septal deviation
2. Chronic Nasal Obstruction
- hypertrophied pharyngeal lymphoid tissue (adenoids and
tonsils)
- hypertrophied gingival mucosa and halitosis
- middle ear abnormalities - retracted, scarred ears with
serous otitis media
INVESTIGATIONS
- for eosinophilia (>10-20%) with Wright or Eosin/Methylene
Blue stains
2. Serum
- eosinophilia
- elevated IgE
3. Allergy Tests
- In Vivo - skin tests - immediate, delayed, patch skin test
- In Vitro - Immunoassays - RAST, MAST, ELISA
4. Imaging Studies
- to rule out acute or chronic sinusitis
MANAGEMENT:
- identify allergens and trial of avoidance therapy
- remove offending pets from house
- management of dust mites with plastic covers, rug removal,
and washing of stuffed animals
2. Prophylactic Therapy
- multifactorial relief of inflammation by decreasing:
- capillary permeability; mucosal edema (vasoconstrictor
effect); mucous production; number of mast cells,
basophils, eosinophils, and neutrophils; hyperactivity of
the nasal mucosa; mediators of inflammation
2. Action
- useful in the prophylactic management of both seasonal
and perennial allergic rhinitis (i.e., begin use 1 week
before exposure to allergen - pollens)
- therapeutic effects may not be seen for 5-7 days
- side effects:
- hypothalamic-pituitary axis suppression with long term
use, nasal mucosa atrophy, nasal irritation
3. Dose
- fluticasone propionate suspension
- 1 application (50 ug) in each nostril od
- less than 1% oral bioavailability
2. Beconase
- beclomethasone dipropionate suspension
- 2 applications (100 ug) in each nostril bid
3. Rhinocort
- budesonide powder
- 2 applications (200 ug) in each nostril od
- 11% oral bioavailability
2. Sodium Cromoglycate (Rynacrom)
- stabilizes the mast cell membrane thus inhibiting
mediator release
- may block calcium channels in the plasma membrane of the
mast cells and prevent calcium transport across the plasma
membrane
- prevents both the early and late responses to an
allergen
- does not stabilize the basophil membrane and does not
inhibit the binding of IgE to mast cells or basophils
2. Action
- prevents sneezing, rhinorrhea, and nasal itching in
patients with seasonal and allergic rhinitis (but not nasal
congestion)
- side effects:
- irritability, hypersensitivity
3. Dose
- initial - 1 spray per nostril 6 times per day
- maintenance - 1 spray per nostril 2-3 times per day
2. Acute Therapy
- Histamine H1-Receptor antogonist
2. Action
- prevents nasal symptoms (rhinorrhea, nasal itching,
sneezing) and conjunctival symptoms (itching, tearing,
erythema)
- exerts maximal effect if taken before anticipated
exposure (i.e., begin use 2 days before exposure to antigen)
- peak action hours after peak serum concentration
achieved
- newer ones (Seldane, Hismanal) are lipophobic and thus
do not cross the blood-brain barrier, i.e., are not sedating
- contraindications
- hypersensitivity reactions
- side effects
- fatigue, dry mouth, somnolence
3. Doses
- 15 mg po bid (3-6 years of age)
- 30 mg po bid (7-12 years of age)
- 60 mg po bid (>12 years of age)
2. Hismanal (Astemizole)
- 2 mg/10kg/d od (<6 years of age)
- 5 mg po od (6-12 years of age)
- 10 mg po od (>12 years of age)
3. Claritin (Loratodine)
- 10 mg po od (>12 years of age)
4. Reactine (Cetirizine)
- 5-10 mg po od (>12 years of age)
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