What are the different types of allergic rhinitis and how are they classified?

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

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
• 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 1, 2
• Patients typically present with more prominent sneezing, rhinorrhea, and ocular symptoms compared to perennial forms 3, 4
• The length of seasonal exposure depends on geographic location and climatic conditions 1

Perennial Allergic Rhinitis (PAR)

• Symptoms occur year-round without seasonal variation 1
• Caused by IgE-mediated response to year-round environmental aeroallergens including dust mites, indoor mold, animal dander (cats, dogs), and certain occupational allergens 1, 2
• Nasal obstruction is the predominant symptom, with episodic sneezing and rhinorrhea occurring only with higher allergen concentrations (e.g., house cleaning, pet exposure) 3, 4

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
• 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
• Persistent: >4 days per week AND >4 weeks per year 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

Four Combined Categories

1. Mild intermittent
2. Mild persistent
3. Moderate/severe intermittent
4. 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 1

Mixed Rhinitis is Extremely Common

• Combined allergic and nonallergic rhinitis (mixed rhinitis) occurs in 44% to 87% of patients with allergic rhinitis 1, 5
• 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 5

Polysensitization is the Rule, Not the Exception

• 72% of allergic rhinitis patients have mixed allergen sensitization (both seasonal and perennial allergens) 4
• Only 17% have pure seasonal sensitization and 11% have pure perennial sensitization 4
• This high rate of polysensitization further challenges the traditional seasonal/perennial dichotomy 4

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 1. The FDA continues to use seasonal/perennial terminology for medication approval, making this classification practically relevant for prescribing 1.