Overview of Allergic Rhinitis

Introduction

• Allergic Rhinitis, also known as hay fever, involves inflammation of the nasal mucosa due to allergens.
• Two types:
  • Seasonal/Intermittent: Occurs during certain seasons (e.g., plant pollination times).
  • Perennial/Chronic: Occurs year-round due to persistent exposure (e.g., mold, dust mites, animal dander).

Epidemiology

• Affects 15-30% of individuals.
• Severity peaks in the 20s-40s.
• Distribution: 20% seasonal, 40% perennial, 40% both.

Associated Conditions & Risk Factors

• Atopic Triad: Allergic rhinitis, atopic dermatitis, and asthma, all linked with increased IgE levels.
• Other risks: Food-induced urticaria (hives), family history, genetic factors (chromosomes 3 & 4), male gender, high socioeconomic status, cigarette smoke exposure in infancy.
• Protective Factors: Breastfeeding, early pet ownership, farm animal exposure.

Pathophysiology

• Early Phase: Within 5-15 mins post-exposure, allergens increase IgE, which binds to mast cells causing cytokine release (histamine, leukotrienes).
• Late Phase: 4-6 hours post-exposure, further cytokine (IL-4, IL-13) release leads to nasal congestion, edema, and eosinophil infiltration.

Clinical Features

• Common Symptoms: Rhinorrhea (clear nasal discharge), sneezing, nasal pruritus.
• Allergic Conjunctivitis: Watery, itchy, red eyes.
• Chronic Symptoms: Postnasal drip, non-productive cough, nasal congestion.
• Other Findings:
  • Allergic salute (nose rubbing), leading to possible nasal crease.
  • Eustachian tube dysfunction (ear popping/crackling sounds).
  • Chronic sinusitis, allergic shiners (dark circles under eyes).
  • Potential asthma and atopic dermatitis.

Diagnosis

• Primarily clinical via history and physical exam.
• Additional methods: Serology testing for allergen-specific IgE, allergy skin tests.
• Note: Avoid skin tests in pregnancy, uncontrolled asthma, cardiovascular disease.
• Medication cessation (e.g., tricyclic antidepressants, anti-IgE, H2 receptor antagonists) before testing.

Treatment

• First Step: Identify and avoid triggers.
• Symptom Management:
  • Saline nasal rinses.
  • Nasal glucocorticoids (first-line treatment).
  • Antihistamines (e.g., diphenhydramine).
  • Leukotriene receptor antagonists in specific cases.

Conclusion

• Understanding and managing allergic rhinitis involves recognizing triggers, applying preventive measures, and employing pharmacological treatments to alleviate symptoms. For further details, explore related full lessons.