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 Eczema

Allergic eczema (atopic dermatitis) is an allergic rash that is usually not caused by skin contact with an allergen. This condition is commonly associated with allergic rhinitis or asthma and features the following symptoms:

• Itching, redness, and or dryness of the skin
• Rash on the face, especially children
• Rash around the eyes, in the elbow creases, and behind the knees, especially in older children and adults (rash can be on the trunk of the body)

Hives

Hives (urticaria) are skin reactions that appear as itchy swellings and can occur on any part of the body. Hives can be caused by an allergic reaction, such as to a food or medication, but they also may occur in non-allergic people. Typical hive symptoms are:

• Raised red welts
• Intense itching

Allergic Shock

Allergic shock (anaphylaxis or anaphylactic shock) is a life-threatening allergic reaction that can affect a number of organs at the same time. This response typically occurs when the allergen is eaten (for example, foods) or injected (for example, a bee sting). Some or all of the following symptoms may occur:

• Hives or reddish discoloration of the skin
• Nasal congestion
• Swelling of the throat
• Stomach pain, nausea, vomiting
• Shortness of breath, wheezing
• Low blood pressure or shock

Shock refers to the insufficient circulation of blood to the body's tissues. Shock is most commonly caused by blood loss or an infection. Allergic shock is caused by dilated and "leaky" blood vessels, which result in a drop in blood pressure.

Allergies - Describe Your Experience

The MedicineNet physician editors ask:

Please describe your experience with allergies.

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