Definition
- An inflammatory condition of the nose characterized by sneezing, rhinorrhea, and obstruction of nasal passages
- Allergic rhinitis comes in 2 varieties:
- Seasonal allergic rhinitis related to environmental allergens present on a temporal basis
- Perennial allergic rhinitis caused by an environment of chronic exposure
- Vasomotor rhinitis is a distinct, nonallergic process.
- A condition of enhanced reactivity of the nasopharynx in which a symptom complex resembling perennial allergic rhinitis occurs with nonspecific stimuli and is felt not to involve immunologic processes
Epidemiology
- Age
- Persons of all ages are susceptible.
- Peaks in childhood and adolescence
- Symptoms generally appear before 40 years of age.
- Prevalence
- ~20% in North America
- ~70% of persons with asthma also experience rhinitis.
- Up to 40% of persons with rhinitis also have asthma.
- Incidence
- Seasonal allergic rhinitis generally occurs from March through early October in North America.
Risk Factors
- Seasonal allergic rhinitis
- Exposure to pollens from grasses, trees, weeds, and molds
- Perennial allergic rhinitis
- Contact with mold spores, cockroach-derived proteins, or house dust containing mite antigens and animal danders
- Family history
- Personal history of collateral allergy expressed as eczematous dermatitis, urticaria, and/or asthma
Etiology
- Nasopharyngeal entrapment of airborne pollens or other allergens results in local release of mediators that cause mucosal hyperemia, swelling, and fluid transudation.
- In up to one-half of patients with perennial rhinitis, no definite allergen can be demonstrated as causative.
- Food allergy is uncommon as a cause of allergic rhinitis.
Associated Conditions
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