Overview of Hay Fever
Hay fever or allergic rhinitis is the inflammation of nose upon reaction to allergens in air. It is usually triggered by environmental allergens, such as dust, pollen, pet hair or mold. Environmental exposure and inherited genetics are associated with hay fever while childhood exposure to animals reduces the risk. Hay fever is manifested by runny nose (clear fluid), sneezing, red, itchy and swollen eyes. Symptoms appear within minutes of exposure and affect sleeping and ability to work and concentrate. People with allergic rhinitis may also have asthma, eczema, allergic conjunctivitis or atopic dermatitis. It is one of the most common allergic reactions all over the world.
Causes and Risk Factors of Hay Fever
Allergic rhinitis has two forms; seasonal and perennial. Seasonal rhinitis is caused by pollens or airborne mold spores and its symptoms appear in spring, summer and early fall. Usually pollens from wind-pollinated plants are predominant cause of allergic reactions. Whereas, perennial rhinitis is caused by dust mites, pet hair, dander, mites or cockroaches and its symptoms can appear year-round in people suffering. Some people may experience both types of rhinitis, with perennial symptoms getting worse during specific pollen seasons. Hay fever can also be triggered be cigarette smoke, perfume, air sprays and diesel exhaust. The underlying mechanism for allergy development involves hypersensitivity IV reactions which involves IgE antibodies attaching to the allergen and causing the release of inflammatory chemicals such as histamine from mast cells.
Signs and Symptoms of Hay Fever
The characteristic features of hay fever include rhinorrhea (excessive nasal discharge), sneezing fits, nasal congestion and obstruction and itching. Other signs include conjunctival swelling, rings under the eyes, erythema (redness on skin and mucosa), eyelid swelling, swollen nasal turbinates and middle ear effusions. Hay fever can be associated with decreased focus, limited activities, irritability, sleep disorder, impaired hand-eye coordination, fatigue and problems remembering things.