Classification of Allergic Rhinitis
Allergic rhinitis is classified using two complementary systems: the traditional temporal pattern classification (seasonal, perennial, episodic) and the ARIA frequency/severity classification (intermittent vs. persistent, mild vs. moderate-severe), with both systems remaining clinically relevant despite defining different patient populations. 1, 2
Traditional Temporal Classification
The traditional system categorizes allergic rhinitis based on timing and pattern of allergen exposure:
Seasonal Allergic Rhinitis (SAR)
- Symptoms occur only during specific seasons when outdoor allergens are present 1, 2
- Caused by IgE-mediated inflammatory response to seasonal environmental aeroallergens including tree pollens (spring), grass pollens (late spring/summer), weed pollens especially ragweed (fall), and outdoor molds 2, 3
- Patients typically present with more prominent sneezing, rhinorrhea, and ocular symptoms compared to perennial forms 4, 5
- The length of seasonal exposure depends on geographic location and climatic conditions 2
Perennial Allergic Rhinitis (PAR)
- Symptoms occur year-round without seasonal variation 1, 2
- Caused by IgE-mediated response to year-round environmental aeroallergens including dust mites, indoor mold, animal dander (cats, dogs), and certain occupational allergens 2, 3
- Nasal obstruction is the predominant symptom, with episodic sneezing and rhinorrhea occurring only with higher allergen concentrations (e.g., house cleaning, pet exposure) 4, 5
Perennial with Seasonal Exacerbations
- Many patients have year-round symptoms that worsen during specific pollen seasons 1
- This pattern is extremely common and represents a significant overlap between SAR and PAR 1
Episodic Allergic Rhinitis
- A newer category denoting allergic nasal symptoms from sporadic exposures to inhalant aeroallergens not usually encountered in the patient's normal environment 1, 2, 1
- Examples include visiting a home with pets when the patient has no pet exposure at home, or visiting a farm with horse exposure 1
ARIA Frequency and Severity Classification
The Allergic Rhinitis and its Impact on Asthma (ARIA) working group proposed an alternative system that discarded seasonal/perennial terminology:
By Frequency
- Intermittent: <4 days per week OR <4 weeks per year 1, 2, 1
- Persistent: >4 days per week AND >4 weeks per year 1, 2, 1
By Severity
- Mild: None of the following are present: sleep disturbance, impairment of daily activities/leisure/sport, impairment of school or work, troublesome symptoms 1
- Moderate-Severe: One or more of the above factors affecting quality of life are present 1, 2
Four Combined Categories
- Mild intermittent
- Mild persistent
- Moderate/severe intermittent
- Moderate/severe persistent 1
Important Clinical Considerations
The Two Systems Define Different Populations
- 44% of patients traditionally classified as seasonal rhinitis have persistent rhinitis according to ARIA classification 1
- 44% with traditional perennial allergic rhinitis were reclassified as intermittent by ARIA criteria 1
- The traditional seasonal/perennial classification remains clinically useful and is used by the FDA for medication approval 2
Mixed Rhinitis is Extremely Common
- Combined allergic and nonallergic rhinitis (mixed rhinitis) occurs in 44% to 87% of patients with allergic rhinitis 1, 6
- Mixed rhinitis is more common than either pure allergic rhinitis or pure nonallergic rhinitis 1
- These patients require intranasal corticosteroids as foundation therapy since they address both allergic and inflammatory components 6
Polysensitization is the Rule, Not the Exception
- 72% of allergic rhinitis patients have mixed allergen sensitization (both seasonal and perennial allergens) 5
- Only 17% have pure seasonal sensitization and 11% have pure perennial sensitization 5
- This high rate of polysensitization further challenges the traditional seasonal/perennial dichotomy 5
Practical Application
For clinical practice, use both classification systems complementarily: the traditional temporal pattern helps predict allergen triggers and timing of symptoms, while the ARIA frequency/severity classification guides treatment intensity and helps assess impact on quality of life 2. The FDA continues to use seasonal/perennial terminology for medication approval, making this classification practically relevant for prescribing 2.