Introduction-to-Allergic-and-Hypersensitivity-Reactions.pptx

Allergic and Hypersensitivity Reactions

1. Presented by:- Ms. Sneha Singh M. Pharmacology. 1 st Sem. (1 st year) Under the Supervision of :- Ms. Priyanka Bajpai Assistant Professor GIPS, Lucknow. Allergic and Hypersensitivity Reactions

2. Introduction to Allergic and Hypersensitivity Reactions Allergic and hypersensitivity reactions occur when the immune system overreacts to harmless substances. These reactions can range from mild to life-threatening.

3. Definition and Types of Allergic Reactions Definition Allergic reactions occur when the immune system mistakenly identifies a harmless substance as a threat. This leads to the release of histamine and other chemicals, causing a variety of symptoms. Types Allergic reactions are categorized into Type I (immediate hypersensitivity) and Type IV (delayed hypersensitivity). Each type involves different immune cells and mediators. Examples Common allergies include food allergies (peanuts, shellfish), pollen allergies, and drug allergies. Some allergens can cause skin reactions, respiratory problems, and gastrointestinal issues.

4. Causes and Risk Factors of Allergic Reactions 1 Genetic Predisposition A family history of allergies increases the risk of developing allergies. This genetic component plays a significant role in susceptibility. 2 Environmental Exposure Exposure to allergens like pollen, dust mites, pet dander, and mold can trigger allergic reactions. Certain environments can contribute to the development of allergies. 3 Lifestyle Factors Factors such as smoking, air pollution, and stress can influence the immune system's response to allergens. These factors can exacerbate or trigger allergic reactions. 4 Early Childhood Exposure Exposure to certain allergens during early childhood may help build tolerance and prevent the development of allergies. However, excessive exposure can also trigger sensitivities.

5. Symptoms and Diagnosis of Allergic Reactions Skin Reactions Hives, eczema, itching, and swelling are common skin manifestations of allergic reactions. These symptoms can vary in severity and location. Respiratory Symptoms Allergic reactions can affect the respiratory system, causing sneezing, runny nose, coughing, wheezing, and difficulty breathing. These symptoms can range from mild to severe. Gastrointestinal Symptoms Allergic reactions can involve the digestive system, leading to nausea, vomiting, diarrhea, and abdominal pain. These symptoms are commonly associated with food allergies. Diagnosis A doctor can diagnose allergic reactions based on symptoms, medical history, and allergy testing. Allergy tests can identify specific allergens that trigger reactions.

6. Immediate and Delayed Hypersensitivity Reactions 1 Immediate Hypersensitivity This reaction is triggered by allergens like pollen, food, or insect venom. It involves the release of histamine and other chemicals, causing rapid symptoms within minutes. 2 Examples of Type I Anaphylaxis is a severe, life-threatening allergic reaction that can cause difficulty breathing, low blood pressure, and loss of consciousness. It requires immediate medical attention. 3 Delayed Hypersensitivity This type of reaction involves T cells and other immune cells and takes longer to develop, typically 24-72 hours. It's often associated with contact dermatitis, drug allergies, and certain food allergies. 4 Examples of Type IV Common examples include poison ivy rash, nickel allergy, and some drug allergies. The reaction is characterized by redness, swelling, itching, and blisters.

7. Treatment and Management of Allergic Reactions Antihistamines Antihistamines block the effects of histamine, reducing symptoms like sneezing, runny nose, and itching. They are available in over-the-counter and prescription forms. Inhalers Inhalers deliver medications directly to the lungs to relieve asthma symptoms, which are often triggered by allergens. They contain bronchodilators to open airways. Epinephrine Epinephrine (adrenaline) is a life-saving medication used to treat anaphylaxis. It constricts blood vessels, opens airways, and reduces swelling. Corticosteroids Corticosteroids are anti-inflammatory medications that can reduce swelling, redness, and itching. They are available in oral, topical, and injectable forms.

8. Prevention and Avoidance Strategies Avoid Allergens Identify and avoid common allergens like pollen, dust mites, pet dander, food allergens, and medications. Environmental Control Use air purifiers, dust mite covers, and vacuum cleaners with HEPA filters to minimize exposure to allergens. Allergy Shots Allergy shots (immunotherapy) can desensitize the immune system to specific allergens over time. It involves regular injections of increasing doses of the allergen. Medication Management Take prescribed medications as directed to prevent or manage symptoms. Antihistamines, corticosteroids, and other medications can help control allergies.

9. Conclusion and Key Takeaways Understanding the Immune System Allergic reactions occur when the immune system overreacts to harmless substances. Identifying Allergens It's crucial to identify specific allergens that trigger reactions to avoid them. Treatment Options Various treatments and management strategies are available to alleviate allergy symptoms. Lifestyle Modifications Modifying lifestyle habits and environment can reduce exposure to allergens. Prevention and Avoidance Early prevention and avoidance strategies are crucial to minimize the impact of allergies.

10. What is the permanent solution of allergy? A llergy shots (allergen immunotherapy)  can be a good option. Also known as desensitization, this treatment involves regular injections containing tiny amounts of the substances that cause your allergies. Over time, these injections reduce the immune system reaction that causes symptoms.

11. References https://www.healthdirect.gov.au/allergies-and-hypersensitivities https://www.ncbi.nlm.nih.gov/books/NBK10756/