Allergic Rhinitis

Allergic rhinitis is an IgE mediated inflammatory disease of the nasal mucosa. IgE antibodies are attached to mast cells near mucosal surfaces. When the individual comes into contact with airborne allergens, the mast cells release chemical mediators histamine, leukotrienes, kinins, and prostaglandins. These substances cause the reactions that lead to the allergic symptoms. The initial response is followed by a late, chronic inflammatory phase characterized by the proliferation of mast cells, the invasion of the mucosa by eosinophiles, basophiles, and the proliferation of lymphocytes. This inflammatory response causes the increased sensitivity to non-specific stimuli like smoke, strong odors, and insecticides. Allergic rhinitis affects about 10-20% of the pediatric population and may be seasonal (pollens and grasses) or perennial (animals, dust mites, cockroaches).

 

Common Symptoms

  1. Itching of the nose, eyes, throat 
  2. Sneezing and stuffiness
  3. Watery nasal discharge and post nasal drip
  4. Chronic cough
  5. Persistent serous otitis media
  6. Headache
  7. Watery eyes and swelling around the eyes.

- Symptoms may occur upon exposure to an allergen or at a later time. Symptoms may also be intermittent or persistent.

Diagnosis

  1. Symptom complex
  2. Family history (80% have FH of allergic disorder)
    1. If both parents have allergies, 75% risk
    2. If one parent has allergies, 50% risk
  3. Environmental history and exposure
  4. History of urticaria and eczema
  5. Physical findings
    1. Afebrile
    2. Pale and boggy nasal mucosa, may be pale blue
    3. Dark circles under the eyes thought to be secondary to venous congestion ("allergic shiners")
      shiners_1_0.jpg
      http://www.honolulueyeclinic.com/blog/?attachment_id=438
       
    4. Horizontal crease on the nose due to allergic "salute"
      image202_1_0.jpg 
      Marks M: Physical Signs of Allergy of the Respiratory Tract in Children. New York, American College of Allergy, Asthma and Immunology, 1990
    5. "Rabbit nose"
      image204_0.jpg
      Marks M: Physical Signs of Allergy of the Respiratory Tract in Children. New York, American College of Allergy, Asthma and Immunology, 1990
    6. Evidence of allergies such as eczema
    7. Mouth breathing
  6. Skin testing: pretest probability of allergic rhinitis exceeds treatment threshold for most patients, so treatment without diagnostic testing is recommended.

 

Complications

  1. Poor functioning in school and other activities
  2. Irritability
  3. Poor concentration and increased sleepiness
  4. Acute otitis media and sinusitis
  5. Adverse side effects of treatment (see below)

 

Treatment

  1. Antihistamines- Competitive inhibitors for histamine at the mast cell H1 receptor sites. May also be related to anticholinergic affect. Should be given prior to exposure if possible. Peak levels at 5-7 hours after dose.
    1. First generation- Penetrate the central nervous system (CNS) and cause drowsiness, slow reaction time, and impair learning. (Benadryl, Brompheneramine, and Chlortrimeton)
    2. Second generation- Lipophobic and will not cross into the CNS. Less frequent dosing than first generation. (Claritin and Zyrtec)
    3. Intranasal
  2. Decongestants- Decrease blood flow to the tissues and improve patency of the nasal passages. May be combined with antihistamines. Topical decongestants may cause rhinitis medicamentosa which increases obstruction and should not be used for longer than 3 days.
  3. Intranasal Steroids- These are anti-inflamatory and decrease mucous production and edema. Should be used regularly rather than on an as-needed basis. Twice a day dosing. There are no associated systemic effects. Some believe intranasal steroids should be the first line of therapy (e.g. Vancenase, Beconase, Flonase, Nasacort).
  4. Cromolyn- Inhibits the release of histamine, and anti-inflammatory activity. Used as a maintenance prophylaxis. Very good safety record and well tolerated. Needs to be given initially four times a day, therefore compliance may be a problem.
  5. Leukotiene blockers- Can be useful especially in combination with first line therapies (e.g. Montelukast/Singulair).
  6. Immunotherapy- Alters the immune reactivity to antigens. May take up to 6-12 months to see results. Should be saved for selected patients that have failed medical management or have had intolerable side effects from medications. Should be skin tested and evaluated by a pediatric allergist. Make sure that positive skin test correlate with the symptoms.  Skin tests should not be performed on children <3 y.o.
  7. Environmental changes - Avoidance of allergens
    1. Eliminate dust and dust mites in the environment as best as possible
      1. Mattress covers
      2. Keep humidity down to decrease mold exposure.
      3. Eliminate carpeting and stuffed animals.
    2. Air conditioners and air purifiers
    3. Avoid pets if possible
    4. Keep windows closed at night and the early morning when the pollen counts are highest.
    5. Wash child's hair and pets frequently to eliminate the carriage of pollen and allergens
    6. Decrease mold exposure in the home.
    7. Avoid cigarette smoke
    8. Dust mite elimination.

 

References

  1. Lasley MV and Shapiro GS. Testing for Allergy.  Pediatrics in Review. 2000; 21:39-43.
  2. Fireman P. Therapeutic Approaches to Allergic Rhinitis.  Treating the child.  J. of Allergy and clinical Immunology 2000; 105 S 616-21.
  3. Simons F.E. Advances in H1-Antihistamines. NEJM Nov 18, 2004
  4. Todd A. and Sheth K. Update on Allergic Rhinitis.  Pediatrics in Review August 2005
  5. Plaut M. and Valentine M. Allergic Rhinitis.  NEJM November 3, 2005
  6. Diagnosis and Management of Rhinitis: Updated Practice Parameter.  Journal of Allergy and Clinical Immunology.  2008;122 S1-84.
  7. Rachelefsky,g. and Farrar JR. A Control Model to Evaluate Pharmocotherapy for Allergic Rhinitis in Children.  JAMA Pediatrics March 2013

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