Management of Allergic Rhinitis

Allergic Rhinitis

IgE-mediated nasal disorder from allergen exposure.

Rhinorrhea

Medical term for runny nose symptom.

main symptoms

rhinorrhoea

nasal itching

congestion

sneezing

how many people suffer gobally

400 million

geographical high prevalance

Australia

new Zealand

uk

What is chemotaxis?

Movement of immune cells towards allergen sites.

What is activated during chemotaxis?

Chemocytes.

What type of antibody is synthesized in response to allergens?

IgE.

What happens when IgE cross-links with an allergen?

It triggers hypersensitivity.

What substances are released during an allergic reaction?

Histamine, tryptase, prostaglandins, and leukotrienes.

Eosinophils

White blood cells involved in allergic reactions.

Histamine Release

Chemical causing allergic symptoms like itching.

IgE Synthesis

Production of immunoglobulin E in response to allergens.

Sensory Nerve Activation

Triggers sneezing and nasal itch during allergies.

Mucus Cell Production

Increased mucus secretion during allergic reactions.

other causes

infectious

drug induced

hormonal

idiopathic

Persistent vs Intermittent

majority of a week vs less than 4 days a week

Rhinoscopy

Examination of nasal passages for diagnosis.

Socrates

Site

Onset

Character

Relieving factors

Associated symptoms

Timing

Exacerbating features

Severity

taking a history

age

sex

socrates

Differential Diagnosis

Identifying other conditions mimicking allergic rhinitis.

Other diagnostic tests

rhinoscopy

allergy tests

cytology of nasal secretion

CT scan

Mast Cell Stabilizers

Medications preventing histamine release from mast cells.

Sodium Cromoglicate

Mast cell stabilizer used for allergic symptoms.

OTC

eyedrop

6+

no contacts

Antihistamines

Drugs blocking histamine effects, alleviating symptoms.

Nasal Irrigation

Saline solution used to clear nasal passages.

Beclomethasone

Corticosteroid nasal spray for allergy symptoms.

corticosteroid

topical

18+

2 sprays each morning and night

blow nose before use to clear mucus

Corticosteroid

Anti-inflammatory medication effective for nasal symptoms.

Topical effect

Localized action at the site of application.

H1 Receptor Antagonists

Block histamine effects, alleviating allergic symptoms.

1st Generation Antihistamines

Sedating; include diphenhydramine and chlorphenamine.

not usually given for allergic rhinitis

chlorphenamine is the drug of choice

2nd Generation Antihistamines

Non-sedating; include loratadine and cetirizine.

commonly sold for allergic rhinitis

other uses of first generation H1 antagonist

sedating

can be useful if patients symptoms are disturbing sleep

Antiemetic (nausea and vomiting associated with conditions)

general properties of 1st generation H1 antagonists

lipid soluble

well absorbed

metabolized in the liver

half life around 5-6 hours

clinically relevant interactions of antihistamines

sedative effect

- opioids and alcohol

anti-muscarinic effect

- TCAs

-oxycontin

azoles

- increase exposure of antihistamines

- QT prolongation

QT prolongation

Potential heart rhythm issue with certain antihistamines.

general properties of 2nd generation H1 antihistamines

- lipid structure with highly ionised functional group

-less CNS penetrations

-well absorbed

- metabolized in the liver

- half life 6+

- lower incidence of adverse effects

Cetirizine

Common non-sedating antihistamine; 10mg OD for adults.

mast cell stabilizer and anti-muscarinic

Azelastine

Nasal spray formulation for allergic rhinitis.

Insomnia preparations

Contain diphenhydramine for sleep disturbances.

Antiemetic

Medication for nausea and vomiting relief.

Loratadine

Most commonly used non-sedating antihistamine.

GSL and P

10mg once daily 6+

Mast cell stabilizer

Prevents release of histamine from mast cells.

Fluticasone

Another corticosteroid nasal spray option.