(11) Allergy

Allergic rhinitis:

Nonallergic rhinitis:

Allergic rhinitis: Itching (itchy eyes), Sneezing, watery runny nose

Nonallergic rhinitis: Little/no itching or sneezing, possible loss of smell.

What are the main allergy medication classes?

1. Intranasal corticosteroids

2. Antihistamines

3. Mast cell stabilizers

4. Decongestants

Allergy Classification

Type	Memorize
Episodic	Unusual allergen exposure
Intermittent	≤4 days/week OR ≤4 weeks
Persistent	>4 days/week AND >4 weeks
Mild	No impairment of sleep/activities
Moderate–severe	Impairment OR troublesome symptoms

⭐ Professor's case: Visits family with dog → sneezing/itching → improves after shower →

Mild episodic allergic rhinitis.

Treatment Selection

Patient	Preferred treatment
intermittent Episodic / Mild intermittent	Oral or intranasal antihistamine
intermittent Moderate–severe	Antihistamine INCS or INCS + INAH (second-line)
persistent Mild	Intranasal corticosteroid (INCS)
persistent Moderate–severe	INCS + intranasal antihistamine (INAH)

Intranasal Corticosteroids (INCS)

topics

• drugs

• facts

Intranasal Corticosteroids (INCS)

drugs

Generic	Brand
Fluticasone	Flonase
Budesonide	Rhinocort
Mometasone	Nasonex
Triamcinolone	Nasacort

Intranasal Corticosteroids (INCS)

facts

TIMELINE

• Full effect → ≥1 week.

• Start ≥1 week before expected allergies..

TREAT

• Treat all allergy symptoms + congestion.

• Low systemic absorption → Few drug interactions.

COUNSEL

• AE: Minor nasal irritation, sneezing, sore throat.

• Prime before first use/after nonuse; shake gently.

• Use regularly, NOT PRN.

Antihistamines

topics overview

• types of antihistamine and drug of each type:

  • Oral — 2nd Generation (Preferred)

  • Oral — 1st Generation (Generally Avoid)

  • Intranasal Antihistamine

Antihistamines

Oral — 2nd Generation (Preferred)

Generic	Brand
Loratadine	Claritin
Cetirizine	Zyrtec
Fexofenadine	Allegra
Levocetirizine	Xyzal

• ❌ DO NOT treat congestion and cold symptoms! JUST ALLERGIES

• Rapid relief: Itching, sneezing, runny nose

• If ineffective → Trial another antihistamine.

Antihistamines

Oral — 1st Generation (Generally Avoid)

• Diphenhydramine (Benadryl)

• Doxylamine (Unisom)

• Chlorpheniramine (Chlor-Trimeton)

Why avoid? Sedation + anticholinergic effects.

• Avoid in older adults.

• Contraindicated in BPH and angle-closure glaucoma.

• Treat allergies and colds/cough, not conjunction!

Antihistamines

Intranasal Antihistamine

Azelastine (Astepro)

• ✅ Treats congestion, unlike oral antihistamines.

• May combine with INCS for severe symptoms.

• Onset: 30 minutes; duration: 24 hours.

• Dose ≥12 years: 2 sprays/nostril, 1–2× daily.

Mast cell stabilizers

Cromolyn Sodium (NasalCrom) ⭐

• Preventive → Start before allergy symptoms.

• Minimal adverse effects.

• Initial benefit: 3–7 days.

• Maximum benefit: 2–4 weeks.

• Dose: 3–6×/day.

Decongestants

topics

• MOA- Adrenergic agonists → Relieve nasal/sinus congestion.

• Types

  • Oral Decongestants

  • Intranasal Decongestant

Oral and Nasal Decongestants

topics

• drug

• AE

• Contraindicated

• Counsel

Oral Decongestants

1. Drug

Drug	Remember
Pseudoephedrine	Preferred/effective
Oral phenylephrine (Sudafed)	❌ Lacks efficacy

2. Adverse effects:

• CV → ↑ BP, ↑ HR, palpitations.

• CNS → Insomnia, anxiety, restlessness.

3. Contraindicated:

• Heart problems

  • Arrhythmias, CAD, MI, angina.

  • Uncontrolled hypertension.

• On Antidepressants

  • MAOIs → Wait 2 weeks after stopping.

  • Caution with SSRIs/SNRIs.

4. Counsel

• Avoid near bedtime.

Intranasal Decongestants

1. Drug

Drug	Duration
Oxymetazoline (Afrin)	12 hours
Phenylephrine	4–6 hours

2. Adverse effects:

   • Burning, stinging, dryness.

3. Contraindicated:

   • Caution with hypertension.

   • Prolonged use → Rebound congestion (rhinitis medicamentosa).

4. Counsel

   • Limit to 3–5 days.