Allergy

In this Article

• What does an allergy mean?
• What causes allergies?
• Who is at risk and why?
• What are common allergic conditions and their symptoms and signs?
• Hay Fever
• Asthma
• Allergic Eyes
• Allergic Eczema
• Hives
• Allergic Shock
• Where are allergens? Everywhere
• In the air we breathe
• In what we ingest
• Touching our skin
• Injected into our body
• Allergy At A Glance
• Pictures of Common Allergy Triggers - Slideshow
• Pictures of Pets and Allergies - Slideshow
• Pictures of Home Allegy - Slideshow
• Patient Discussions: Allergies - Describe Your Experience

Allergic Rhinitis

Allergic rhinitis ("hay fever") is the most common of the allergic diseases and refers to seasonal nasal symptoms that are due to pollens. Year round or perennial allergic rhinitis is usually due to indoor allergens, such as dust mites, animal dander, or molds. It can also be caused by pollens. Symptoms result from the inflammation of the tissues that line the inside of the nose (mucus lining or membranes) after allergens are inhaled. Adjacent areas, such as the ears, sinuses, and throat can also be involved. The most common symptoms include:

• Runny nose
• Stuffy nose
• Sneezing
• Nasal itching (rubbing)
• Itchy ears and throat
• Post nasal drip (throat clearing)

In 1819, an English physician, John Bostock, first described hay fever by detailing his own seasonal nasal symptoms, which he called "summer catarrh." The condition was called hay fever because it was thought to be caused by "new hay."

Asthma

Asthma is a breathing problem that results from the inflammation and spasm of the lung's air passages (bronchial tubes). The inflammation causes a narrowing of the air passages, which limits the flow of air into and out of the lungs. Asthma is most often, but not always, related to allergies. Common symptoms include:

• Shortness of breath
• Wheezing
• Coughing
• Chest tightness

Allergic Eyes

Allergic eyes (allergic conjunctivitis) is inflammation of the tissue layers (membranes) that cover the surface of the eyeball and the undersurface of the eyelid. The inflammation occurs as a result of an allergic reaction and may produce the following symptoms:

• Redness under the lids and of the eye overall
• Watery, itchy eyes
• Swelling of the membranes

Allergies - Describe Your Experience

The MedicineNet physician editors ask:

Please describe your experience with allergies.

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