Aetiology

Seasonal rhinitis is most commonly an allergic reaction to pollen, usually grasses and trees.

Perennial allergic rhinitis is most commonly a reaction to:

• dust
• mites found in mattresses, carpets, furry toys
• feathers
• animal dander—most commonly cats and dogs
• occupational allergic rhinitis is caused by allergens found at work, e.g., people working with latex gloves, bakers (flour dust), wood dust (1)

However, note that:

• many patients are allergic to both seasonal and perennial allergens, and may have perennial symptoms without seasonal exacerbations
• a succession of seasonal allergens may mask seasonality

Reference:

1. Clinical knowledge summaries, safe practical clinical answers. Allergic rhinitis