Rhinitis, Allergic

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.

• Hay fever
• Pollinosis

• Inflammation of nasal passages caused by allergic reaction to airborne substances.

• 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.

• 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.

• Affects about 50 million Americans of all ages.
• Prevalence of seasonal rhinitis between 1–40%; perennial rhinitis prevalence ranges from 1–13%.

• Allergen avoidance important to prevent episodes but often difficult to accomplish.

• Genetics
• Allergen exposure

Signs and Symptoms

• 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.

Means of Confirmation and Diagnosis

• Medical history for:
  • Description of symptoms
  • Environmental factors and exposures
  • Results of previous therapy
  • Use of medications
  • Previous nasal injury or surgery
  • Family history

Laboratory Tests

• Radioallergosorbent test (RAST) to detect IgE antibodies in blood specific for given antigen.
• Peripheral blood eosinophil count may be elevated but is nonspecific finding.

Diagnostic Procedures

• Percutaneous allergy testing can help determine whether rhinitis caused by immune response to allergens.
• Microscopic examination of nasal scrapings typically reveals numerous eosinophils.

Differential Diagnosis

• Viral rhinitis (common cold)
• Viral conjunctivitis
• Vasomotor rhinitis
• Acute or chronic sinusitis
• Rhinitis medicamentosa
• Nasal polyposis
• Foreign body

• Minimize or prevent symptoms with minimal side effects and reasonable medication expense.
• Maintain normal lifestyle, including participation in outdoor activities and interaction with pets.

• Figure 1: Treatment algorithm for allergic rhinitis

• Allergen avoidance
  • Reduce household mold growth by keeping humidity below 50% and removing obvious growth with bleach or disinfectant.
  • Remove pets that cause symptoms from home, if ...