Allergic Rhinitis (AR) arises due to the hypersensitivity of the body’s immune system to environmental triggers. Allergens are substances that evoke allergy in a susceptible person. When this person breathes in an allergen such as pollen or dust, the body releases chemicals like histamine. This leads to itching, swelling, and mucus production.

Allergens like seasonal pollens and moulds are responsible for seasonal AR (SAR). Rhinitis that does not have a clearly defined seasonal association is termed perennial AR (PAR). PAR is caused by indoor allergens like house dust mites and animal proteins. Dust mites and cats produce the most important indoor allergens. Allergic rhinitis due to outdoor triggers, such as plant pollen is commonly called hay fever.

Common causes of hay fever include:

• Trees (deciduous and evergreen)
• Grass
• Ragweed

Hot dry windy air carries large amounts of pollen and can cause hay fever.

Common causes for Perennial Allergic Rhinitis (PAR) include:

• Indoor fungi
• Animal dander, the most important being cat’s. Dander from rodents, rabbits, dogs, and birds could also cause rhinitis
• Dust mites
• Other insects (esp. cockroach, gypsy moths, crickets, ladybugs, spiders, and beetles)

Allergies may be associated with disorders like eczema and asthma. Genes and environment makes one prone to AR. Susceptibility to develop allergies runs in families. If both parents have allergies, you are prone to have allergies. If your mother has allergies, chances of AF are even greater.

Symptoms include sneezing, nasal congestion, nasal itching, and runny nose. Diagnosis is usually based on a person's history of symptoms. A family history can usually be elicited.

Blood tests and skin tests help to diagnose the condition and detect the allergen. Completely avoiding allergens is not practically possible though it is the only perfect solution.

Nasal corticosteroid sprays and antihistamine medications are often used to treat allergic rhinitis.