Environmental Allergy (Allergic Rhinitis) and Hay Fever Medications

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Medical Author:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

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.

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• What Are Allergies?
• What Are the Risks of Allergies?
• What Medical Treatments Are Used for Allergies and Hay Fever?
• Antihistamines
• Decongestants
• Anticholinergic Nasal Sprays
• Corticosteroid Nasal Sprays
• Antiallergy Eyedrops
• Leukotriene Inhibitors
• Mast Cell Inhibitors
• For More Information
• Synonyms and Keywords
• Authors and Editors
• Related allergy medication article:
  Flonase - on RxList

What Are Allergies?

An allergic reaction occurs when the immune system responds in an abnormal fashion to a substance that is foreign to the body. The immune system normally protects the body from harmful agents like bacteria and toxins. The body's abnormal response to a substance that is usually harmless (called an allergen) is called a hypersensitivity reaction, or an allergic reaction. Generally, these reactions are due to interactions between the allergen and the family of proteins, IgE (immunoglobulin E), resulting in activation of cells in the body called mast cells and basophils. These cells release chemical messengers in the body that cause the symptoms of an allergic reaction.

Many substances in the environment can become allergens but only in genetically susceptible people. Dust mites, molds, animal hair or danders, pollens, medications, foods, and insect venoms are examples of common allergens. Reactions may be in the nose (hay fever), eyes (conjunctivitis), chest (asthma), or it can be systemic (anaphylaxis), meaning it can involve the entire body.

Allergic rhinitis is an inflammation of the nasal membranes (along with membranes of the eyes, eustachian tubes, middle ear, sinuses, and throat) due to an allergic reaction. It is the most common cause of inflammation in the nose (rhinitis). Approximately 20% of the U.S. population is believed to suffer from allergic rhinitis.