Allergic Rhinitis

Pathophysiology of allergic rhinitis

  • Immune mediated disease initiated by an antigen/antibody reaction
    • Seasonal (aka hay fever) generally occurs in the spring/fall
      • Tree, grass, weed pollens
    • Perennial = year round symptoms
      • Mold, Dust, cockroaches, animal hair/shit
      • Inhaled steroids are the treatment of choice for perennial (year-round) allergies
  • IgE plays a big role in determining susceptibility
    • Antigen-specific IgE is produced in genetically susceptible individuals     (inhaled antigens/allergens are responsible for clinical manifestations)
  • Inflammatory process

Clinical symptoms and complications associated with allergic rhinitis

  • early phase symptoms:  rhinorrhea, sneezing, congestion, itching, watery eyes, ears, nose, palate
  • late phase symptoms:  Nasal Congestion, hyperresponsive reactions

Agents used to treat and prevent allergic rhinitis

  • Non-pharmacological:  avoid allergens, air conditioning, dehumidifier (limit mold growth)
  • Pharmacological:   1st gen antihistamines: diphenhydramine, chlorpheneramine, clemastine
    • 2nd gen antihistamines:  cetirizine (most sedating 2nd gen), loratidine, fexofenadine, desloratidine
    • Decongestants (topical or systemic)–only use topical for 3-5 days
      • Systemic:  pseudoephedrine, phenylephrine (doesn’t work as well)
    • Corticosteroids (Fluticasone, mometasone, flunisolide, budesonide)–agent of choice for perennial allergies
      • Reduce inflammation, reduce edema, mild vasoconstriction, inhibit mast-cell mediated late phase reactions, suppress neutrophil chemotaxis
      • May take days/weeks to see effect
    • Leukotriene Modifiers
      • Block action of LKs from the arachidonic acid cascade
      • May be effective as an add-on therapy or in combo with antihistamines
    • Mast cell stabilizers: Cromolyn sodium  (admin prior to season, it has a delayed onset of action)
    • Ipratropium Bromide:  not that effective, local antisecretory properites
    • Allergy desensitization: series of shots
    • Antihistamine eye drops:  zaditor
  • Anticholinergics & surgery are sometimes used but they aren’t as effective of options as the above

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