Syed Shahzad Mustafa, MD
After growing up in the Rochester area, Dr. Mustafa pursued his undergraduate studies at the Johns Hopkins University in Baltimore and attended medical school at SUNY Buffalo. He then completed his internal medicine training at the University of Colorado and stayed in Denver to complete his fellowship training in allergy and clinical immunology at the University of Colorado, National Jewish Health, and Children's Hospital of Denver.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
- Allergy facts
- Allergy overview
- What is an allergy?
- What causes allergies?
- Who is at risk for allergies and why?
- What are common allergic conditions and what are allergy symptoms and signs?
- Allergic rhinitis (hay fever)
- Allergic eyes (conjunctivitis)
- Eczema (atopic dermatitis)
- Hives (urticaria)
- Allergic shock (anaphylaxis)
- Where are allergens?
- In the air we breathe
- In what we ingest
- Touching our skin
- Injected into our body
- Common Allergy Triggers Slideshow
- Take the Quiz on Allergies
- Allergy Proof Your Home Slideshow
- Allergies FAQs
- Patient Comments: Allergies - Describe Your Experience
- Patient Comments: Allergies - Symptoms
- Patient Comments: Allergies - Causes
- Patient Comments: Allergies - Asthma
- Find a local Asthma & Allergy Specialist in your town
- Allergy involves an exaggerated response of the immune system, often to common substances such as foods or pollen.
- The immune system is an intricate system that defends the body against foreign invaders, such as bacteria and viruses, while also surveying for conditions such as cancer and autoimmunity.
- Allergens are substances that are foreign to the body and can cause an allergic reaction.
- IgE is the allergic antibody.
- Allergies can not only develop at any age, but many individuals also outgrow allergies over time.
- While environment plays a role in allergy development, there is a greater risk of developing allergic conditions if a person has a family history of allergy, especially in parents or siblings.
In this review, you will learn how allergy relates to the immune system. You will begin understanding how and why certain people become allergic. The most common allergic diseases are discussed briefly in this article.
What is an allergy?
An allergy refers to an exaggerated reaction by our immune system in response to exposure to certain foreign substances. It is exaggerated because these foreign substances are usually seen by the body as harmless and no response occurs in nonallergic people. In allergic individuals, the body recognizes the foreign substance and one arm of the immune system generates a response.
Allergy-producing substances are called "allergens." Examples of allergens include pollens, dust mites, molds, animal proteins, foods, and even medications. To understand the language of allergy, it is important to remember that allergens are substances that are foreign to the body and can cause an allergic reaction in certain people. When an allergic individual comes in contact with an allergen, the immune system mounts a response through the IgE antibody. Therefore, people who are prone to allergies are said to be allergic or "atopic."
Austrian pediatrician Clemens Pirquet (1874-1929) first used the term allergy. He referred to both immunity that was beneficial and to the harmful hypersensitivity as "allergy." The word allergy is derived from the Greek words "allos," meaning different or changed and "ergos," meaning work or action. Generally speaking, allergy therefore refers to an "altered reaction." The word allergy was first used in 1905 to describe the adverse reactions of children who were given repeated shots of horse serum to fight infection. The following year, the term allergy was proposed to explain this unexpected "changed reactivity."
- Approximately 10% to 30% of individuals in the industrialized world are affected by allergic conditions, and this number is increasing.
- Allergic rhinitis (nasal allergies) affects roughly 20% of Americans. Between prescription costs, physician visits, and missed days of work/school, the economic burden of allergic disease exceeds $3 billion annually.
- Asthma affects roughly 8% to 10% of Americans. The estimated health costs for asthma exceed approximately $20 billion annually.
- The prevalence of allergic conditions has increased significantly over the last two decades and continues to rise.
Next: What causes allergies?
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