By- Dr. Armaan Singh

Allergic rhinitis is an allergic inflammation of the nasal airways. It occurs when an allergen, such as pollen, dust, or animal dander (particles of shed skin and hair) is inhaled by an individual with a sensitized immune system. In such individuals, the allergen triggers the production of the antibody immunoglobulin E (IgE), which binds to mast cells andbasophils containing histamine. When caused by pollens of any plants, it is called pollinosis, and, if specifically caused by grass pollens, it is known as hay fever. While symptoms resembling a cold or flu can be produced by an allergic reaction to pollen from plants and grasses it does not cause a fever. The link with hay came about due to an early (and incorrect) theory that the symptoms were brought about by the smell of new hay (coumarin). A competing popular name was 'hay asthma'.

Sneezing. Rhinorrhea and nasal congestion:This may be either

anterior or posterior, leading to postnasal drip. Clear - infection unlikely. Unilateral - is uncommon. cerebrospinal fluid (CSF) leak should be excluded.Yellow-

coloured implies allergy or infection. Green-coloured is usually associated with infection.

Blood-tinged unilateral - tumour, foreign body or nose picking.

Blood-tinged bilateral - bleeding points, nose picking or granulomatous disorder.

Itchy nose and/or palate.Symptoms tend to be bilateral, and worse on waking.

A survey of adults found that about a third of allergic rhinitis sufferers found that symptoms affected their work, home life and social life.In children, symptoms affected their schoolwork and caused sleep problems.Persistent blockage of intranasal passages occasionally results in rhinosinusitis.In adults, a strong association exists between nasal polyps, asthma and sensitivity to aspirin - Samter's triad.

Non-allergic rhinitis. Infective rhinitis. Nasal polyps. Rhinosinusitis. Adenoidal hypertrophy. Cystic fibrosis. Kartagener's syndrome. Systemic lupus erythematosus and granulomatous conditions, eg Wegener's granulomatosis andsarcoidosis. Consider foreign bodies in the young child.

Other causes of nasal obstruction. Leaking of cerebrospinal fluid will present with watery rhinorrhoea, often unilateral. It is usually associated with trauma (including surgical trauma) or neoplasia, but spontaneous leaking may occur. Nasal neoplasms are rare; the diagnosis should be considered in patients with unilateral symptoms of nasal obstruction, pain or bleeding.

Complications- Sinusitis,Nasal polyps,Chronic otitis media

Investigations- Skin prick test--When skin prick tests are not available or the patient is taking antihistamines or has dermatographism, total and allergen-specific IgE concentrations in the blood may be determined (radioallergosorbent test (RAST)) or enzyme-linked immunosorbent assay (ELISA).