Allergic rhinitis
Allergic rhinitis • It is an IgE mediated immunologic response of nasal mucosa to air-bone allergens and is characterized by watery nasal discharge, nasal obstruction , sneezing and itching in the nose. This may also be associated with symptoms of in the eyes, plate and pharynx. Two clinical types have been rescognized: 1. Seasonal. Symptoms appears in or around a particular season when the pollens of particular plant, to which the patients is sensitive, are present in the air. 2. Perennial. Symptoms are present throughout the year
Allergic rhinitis • Aetiology Inhalant allergens are often the cause. Pollen from the trees and grasses, mould spores, house dust, debris from insects or house mite are common offenders. Food allergy is rarely an important cause. Genetic predisposition plays an important part
Commen allergens • Pollen • Dust mites • Furry animals • Molds • Cockroaches • Stinging insects • Specific foods ➢ milk ➢ eggs ➢ peanuts ➢ wheat ➢ soy ➢ fish/shellfish ➢ tree nuts 30003 30003 15KV 15KV 50U50U
Allergic rhinitis • Pathogenesis 1.Inhaled allergens produce an important part specific IgE antibody in the genetically predisposed individuals. This antibody becomes fixed to the blood basophils or tissues mast cells . 2.On subsequent exposure. Antigen combines with IgE antibody. This reaction produces degranulation of the mast of the cells with release of several chemical mediators
Allergic rhinitis • Pathogenesis
Allergic rhinitis • Pathogenesis These mediator are responsible for symptomatology of allergic disease. Depending on the tissues involved, there may be vasodilation , mucosal oedema, Infiltration with eosinophils, excessive secretion from nasal gland or smooth muscle contraction
Allergic rhinitis • Pathogenesis it is also gets “primed” to other non-specific antigens to which patient was not exposed. Allergic respond occurs in 2 phase: 1. Acute or early phase. 2. Late or delayed phase
Allergic rhinitis • Clinical features There are no age or sex predilection. It may start in infants as young as 6 months or older people. Usually the onset is at 12-16 years of age. The cardinal symptoms of season nasal allergy include paroxysmal sneezing. 10-20 sneezes at a time, nasal obstruction, watery nasal discharge and itching in the nose
Allergic rhinitis • Clinical features