ALLERGY & HYPERSENSITIVITY

Deurali-Janta Pharmaceuticals Pvt. Ltd.

Allergic Rhinitis

Phr. Asad Kamran

AllergyHypersensitivity

“An important undesirable side effect of immunity is the development, under some conditions, of allergy or other

types of immune hypersensitivity.”

Delayed-Reaction AllergyDelayed-reaction allergy is caused by activated T cells and not by antibodies.

In the case of poison ivy, the toxin of poison ivy in itself does not cause much harm to the tissues. However, on repeated exposure, it does cause the formation of activated helper and cytotoxic T cells.

Then, after subsequent exposure to the poison ivy toxin, within a day or so, the activated T cells diffuse from the circulating blood in large numbers into the skin to respond to the poison ivy toxin.

The damage normally occurs in the tissue area where the instigating antigen is present, such as in the skin in the case of poison ivy, or in the lungs to cause lung edema or asthmatic attacks in the case of some airborne antigens.

Allergic PersonThe allergic tendency is genetically passed from parent to child and is characterized by the presence of large quantities of IgE antibodies in the blood.

These antibodies are called reagins or sensitizing antibodies to distinguish them from the more common IgG antibodies.

When an allergen (defined as an antigen that reacts specifically with a specific type of IgE reagin antibody) enters the body, an allergen-reagin reaction takes place and a subsequent allergic reaction occurs.

A special characteristic of the IgE antibodies (the reagins) is a strong propensity to attach to mast cells and basophils.

Allergic PersonAt any rate, many of the mast cells and basophils rupture; others release special agents immediately or shortly thereafter, including histamine, protease, slowreactingsubstance of anaphylaxis (which is a mixture of toxic leukotrienes), eosinophil chemotactic substance, neutrophilchemotactic substance, heparin, and platelet activating factors.

These substances cause such effects as dilation of the local blood vessels; attraction of eosinophils and neutrophils to the reactive site; increased permeability of the capillaries with loss of fluid into the tissues; and contraction of local smooth muscle cells.

Allergic ReactionsAnaphylaxis

Urticaria

Hay Fever

Asthma

Allergic Rhinitis

IntroductionRhinitis is broadly defined as inflammation of the nasal mucosa.

Allergic rhinitis is the most common type of chronic rhinitis, affecting 10 to 20% of the population, and evidence suggests that the prevalence of the disorder is increasing.

In the past, allergic rhinitis was considered to be a disorder localized to the nose and nasal passages, but current evidence indicates that it may represent a component of systemic airway disease involving the entire respiratory tract.

Allergic Rhinitis

IntroductionEvidence has shown that allergen provocation of the upper airways not only leads to a local inflammatory response, but also to inflammatory processes in the lower airways, and this is supported by the fact that rhinitis and asthma frequently coexist.

Therefore, allergic rhinitis and asthma appear to represent a combined airway inflammatory disease, and this needs to be considered to ensure the optimal assessment and management of patients with allergic rhinitis.

Allergic Rhinitis

PathophysiologyIn allergic rhinitis, numerous inflammatory cells, including mast cells, CD4-positive T cells, B cells, macrophages, and eosinophils, infiltrate the nasal lining upon exposure to an inciting allergen (most commonly airborne dust mite fecal particles, cockroach residues, animal dander, moulds, and pollens).

The T cells infiltrating the nasal mucosa are predominantly T helper (Th) in nature and release cytokines (e.g., interleukin IL-3, IL-4, IL-5, and IL-13) that promote immunoglobulin E (IgE) production by plasma cells.

Allergic Rhinitis

PathophysiologyIgE production, in turn, triggers the release of mediators, such as histamine and leukotrienes, that are responsible for arteriolar dilation, increased vascular permeability, itching, rhinorrhea (runny nose), mucous secretion, and smooth muscle contraction.

The mediators and cytokines released during the early phase of an immune response to an inciting allergen, trigger a further cellular inflammatory response over the next 4 to 8 hours (late phase inflammatory response) which results in recurrent symptoms (usually nasal congestion).

Allergic Rhinitis

ClassificationRhinitis is classified into one of the following categories according to etiology:

IgE-mediated (allergic)

Autonomic

Infectious

Idiopathic (unknown)

Traditionally, allergic rhinitis has been categorized as seasonal (occurs during a specific season) or perennial (occurs throughout the year).

allergic rhinitis is now classified according to symptom duration (intermittent or persistent) and severity (mild, moderate or severe).

Allergic Rhinitis

ClassificationRhinitis is considered intermittent when the total duration of the episode of inflammation is less than 6 weeks, and persistent when symptoms continue throughout the year.

Symptoms are classified as mild when patients are generally able to sleep normally and perform normal activities (including work or school); mild symptoms are usually intermittent.

Symptoms are categorized as moderate/severe if they significantly affect sleep and activities of daily living and/or if they are considered bothersome.

Allergic Rhinitis

Etiological ClassificationAllergic Rhinitis

ETIOLOGICAL CLASSIFICATION OF RHINITIS

Type Description

IgE-mediated (Allergic) IgE-mediated inflammation of the nasal mucosa, resulting in eosinophilic and Th2-

cell infiltration of the nasal lining

Further classified as intermittent or persistent

Autonomic Drug-induced (rhinitis medicamentosa)

Hypothyroidism

Hormonal

Non-allergic rhinitis with eosinophilia syndrome (NARES)

Infectious Precipitated by viral (most common), bacterial, or fungal infection

Idiopathic Etiology cannot be determined

Classification (symptoms, duration & severity)INTERMITTENT:

Symptoms 6 weeks

PERSISTENT:

Symptoms continue throughout the year

MILD:

Normal Sleep

No impairment of daily activities, sport, leisure

Normal work/school

No bothersome symptoms

Allergic Rhinitis

Classification (symptoms, duration & severity)MODERATE-SEVERE

Abnormal Sleep or

Impairment of daily activities, sport, leisure or

Problems at work/school or

Bothersome symptoms

Allergic Rhinitis

TreatmentThe treatment goal for allergic rhinitis is relief of symptoms.

Therapeutic options available to achieve this goal include avoidance measures, oral antihistamines, intranasal corticosteroids, leukotriene receptor antagonists, and allergen immunotherapy.

Other therapies that may be useful in select patients include decongestants and oral corticosteroids.

Allergic rhinitis and asthma appear to represent a combined airway inflammatory disease and, therefore, treatment of asthma is also an important consideration in patients with allergic rhinitis.

Allergic Rhinitis

TreatmentAllergic Rhinitis

OVERVIEW OF PHARMACOLOGIC TREATMENT OPTIONS FOR ALLERGIC RHINITIS

Therapy Usual Adult Dose Usual Paediatric Dose

Oral Antihistamines (2nd Generation)

Cetirizine (Reactine) 5-10mg OD 5-10 ml (1-2 teaspoons) OD

(children’s formulation)

Desloratadine (Aerius) 5mg OD 2.5-5 ml (0.5-1.0 teaspoon) OD

(children’s formulation)

Fexofenadine (Allegra) 60mg BD or 120mg OD Not currently indicated for children

under 12 years of age

Loratadine (Claritin) 10mg OD 5-10 ml (1-2 teaspoons) OD

(children’s formulation)

Intranasal Corticosteroids

Beclomethasone (Beconase) 1-2 sprays (42 µg/spray) EN, BD 1 spray (42 μg/spray) EN, BD

Budesonide (Rhinocort) 2 sprays (64 µg/spray) EN, OD or 1

spray BD

2 sprays (64 μg/spray) EN, OD or 1

spray EN, BD (do not exceed 256 μg)

Ciclesonide (Omnaris) 2 sprays (50 µg/spray) EN, OD Not indicated for children under 12

years of age

Fluticasone Furoate (Avamys) 2 sprays (27.5 µg/spray) EN, OD 1 spray (27.5 μg/spray) EN, OD

Fluticasone Propionate (Flonase) 2 sprays (50 µg/spray) EN, OD or BD

(for severe rhinitis)

1-2 sprays (50 μg/spray) EN, OD

Mometasone Furoate (Nasonex) 2 sprays (50 µg/spray) EN, OD 1 spray (50 μg/spray) EN, OD

Triamcinolone Acetonide

(Nasacort)

2 sprays (55 µg/spray) EN, OD 1 spray (55 μg/spray) EN, OD

Leukotriene Receptor Antagonists

Montelukast (Singulair) 10mg OD Not currently approved for patients

under 15 years of age

Allergic Rhinitis

Asad Kamran

Technical Consultant, MPD

Deurali-Janta Pharmaceuticals Pvt. Ltd.