IgE-mediated allergic reaction (type I hypersensitivity)

Aetiology

Intermittent

• Symptoms <4 days per week or symptoms for <4 weeks
• Grass pollen, tree pollen, fungal spores

Persistent

• Symptoms >4 days per week AND >4 week duration
• House dust mite, cat, dog

Pathophysiology

• IgE-mediated allergic reaction (type I hypersensitivity) results in the generation of histamine and leukotrienes

Classification

• Mild: does not affect patient's day to day life significantly)
• Moderate-severe: involves e.g. abnormal sleep, impairment of daily activities, missing school/work
• (This is in untreated patients)

Clinical features

• Sneezing, nasal itching, nasal discharge and nasal congestion
• Allergic crease indicates repeated itching of nose

Investigations

If diagnostic doubt: