Allergic Rhinitis - Chapter 11

Study Notes

Allergic rhinitis is a systemic condition affecting primarily the upper respiratory tract.
20% of adults and 40% of children in the US are affected.
Four phases: sensitization (initial exposure, IgE production), early phase (rapid mast cell mediator release), cellular recruitment (eosinophils to nasal mucosa leading to inflammation), late phase (mucus hypersensitivity and lower threshold).
Risk factors include family history, skin barrier issues, protein gene mutations, higher IgE levels before age 6, higher socioeconomic status, eczema, and a positive skin allergy test.
Triggers include outdoor allergens (pollen, diesel), indoor allergens (dust, roaches, mold, smoke, pet dander), and occupational allergens (chemicals, latex, resin).
Systemic antihistamines are not recommended for children aged 2-6 years old, exceptions include cetirizine, fexofenadine, levocetirizine and loratidine.
For adults over 65, only loratidine is recommended but under advice of a PCP, cetirizine, levocetirizine, and fexofenadine may be used.
First, classify symptoms based on duration and severity.

Children under 12 years.
Pregnant or breastfeeding women.
Symptoms of nonallergic rhinitis (Table 11-11).
Symptoms of otitis media, sinusitis, bronchitis, or other infections.
Symptoms of undiagnosed, uncontrolled asthma (wheezing, shortness of breath), COPD, or other respiratory disorders.
Severe or unacceptable treatment side effects.

Evaluate patient history, previous therapies, and symptoms.
Determine if exclusions apply (see box).
If no exclusions, recommend control measures for allergen exposure and drug therapy based on patient symptoms.
For symptoms like sneezing, rhinorrhea, or itching, a possible treatment is oral antihistamine (AH).
Mild allergic rhinitis (IAR): use INCS or oral AH
Moderate-to-severe IAR: INCS (preferred) or oral AH
Mild PER: INCS (preferred) or oral AH
Moderate-to-severe PER: INCS (preferred) or oral AH
Evaluate symptoms in 2-4 weeks.
If symptoms persist, add oral or topical decongestants.
If symptoms controlled, reduce dosage and continue treatment for one month.
If not controlled, increase dose, consider combination therapy, or switch drugs; re-evaluate in 1–2 weeks.
Referral to a healthcare provider is necessary if symptoms worsen or do not improve despite treatment.
Adherence to treatment is paramount; evaluate patient adherence.

Antihistamines: These work by competing with histamine at histamine 1 receptor sites, preventing histamine interaction and mediator release. They relieve itching, sneezing, and runny nose, but not nasal congestion.
- First-generation (non-selective): Sedating; highly lipophilic, cross BBB easily, many drug interactions, dangerous in high doses, cardiac and CNS symptoms (sedation, tremors). Examples include chlorpheniramine, clemastine, and diphenhydramine.
- Second-generation (peripherally selective): Non-sedating; examples include cetirizine, levocetirizine, loratidine, and fexofenadine. More common side effects may include CNS depression and stimulation and anticholinergic effects.
Intranasal Glucocorticoids: Effective for itchy eyes, nose, sneezing, runny nose and congestion.
- Examples: triamcinolone acetonide (Nasacort), flonase (fluticasone).
- Minimal systemic absorption, especially after shaking the bottle before use. Side effects may include nasal discomfort, bleeding, sneezing, vision changes, glaucoma, cataract infection, and growth inhibition (caution with use in those under 12 years old).
Intranasal Cromolyn Sodium: Approved for patients ≥5 years old, helps prevent and treat symptoms of allergic rhinitis.

Non-pharmacological treatment includes allergen avoidance (checking pollen count, keeping windows closed, reducing indoor triggers, and washing bedding).
Classify symptoms based on duration (intermittent or persistent) and severity (mild or moderate-severe).
Differentiate allergic rhinitis from non-allergic rhinitis; non-allergic cases require medical referral.
Special populations (pregnancy, lactation, children under 12, elderly) require different treatment recommendations.
Refer to a PCP (primary care physician) if unsure.

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