Allergies
Exaggerated immune responses to certain environmental antigens (allergens), involving IgE antibodies and mast cells.
What is Allergies?
A substance that causes an allergic reaction, typically a foreign protein or chemical that provokes an exaggerated immune response in susceptible individuals.
Key points
- Define allergy and allergen.
- Explain the mechanism of allergic reactions.
- Identify the role of IgE, mast cells, and histamine.
- Differentiate between sensitization and effector phases.
Common exam trap
Confusing allergies with infections.
Definitions
- Term
Allergen
- Meaning
A substance that causes an allergic reaction, typically a foreign protein or chemical that provokes an exaggerated immune response in susceptible individuals.
- Term
Allergy
- Meaning
A hypersensitive or abnormal immune response by the body to substances that are usually harmless.
- Term
IgE
- Meaning
Immunoglobulin E, a class of antibodies produced by the immune system that plays a key role in allergic reactions and defense against parasitic worms.
- Term
Mast Cells
- Meaning
A type of white blood cell found in connective tissues throughout the body that contains granules rich in histamine and heparin, involved in allergic reactions and inflammation.
- Term
Histamine
- Meaning
A compound released by cells in the body that causes the small blood vessels to expand and the walls of the blood vessels to become more permeable, leading to symptoms like itching, swelling, and redness.
- Term
Anaphylaxis
- Meaning
A severe, potentially life-threatening allergic reaction that can occur rapidly after exposure to an allergen, characterized by symptoms such as difficulty breathing, a drop in blood pressure, and swelling.
Learning objectives
Define allergy and allergen.
Explain the mechanism of allergic reactions.
Identify the role of IgE, mast cells, and histamine.
Differentiate between sensitization and effector phases.
Recognize the symptoms and potential severity of allergies.
Prerequisites
Basic immunology (types of immunity, immune cells).
Antibody structure and function (especially IgE).
Inflammatory response.
Common mistakes
Confusing allergies with infections.
Underestimating the severity of allergic reactions.
Not understanding the role of IgE antibodies.
Mistaking symptoms of allergies for common cold.
Keywords
Allergy
Allergen
Hypersensitivity
IgE
Mast Cells
Basophils
Histamine
Anaphylaxis
Immune Response
Inflammation
Practice preview
What type of antibody is primarily involved in allergic reactions?…
easy
Which of the following is a common symptom of an allergic reaction?…
easy
Which cells play a crucial role in releasing histamine during an allergic response?…
easy