Allergic disorder

Question 1

What is allergic disorder?

Answer 1

A misguided reaction to foreign substances by the immune system, the body system of defence against foreign invaders, particularly pathogens (the agents of infection). 

Question 2

What causes an allergic disorder?

Answer 2

1. Conditions caused by hypersensitivity of the immune system to typically harmless substances
2. IgE binds to receptor on mast cell or basophil, triggering release of histamine
3. Causes → dust, foods, latex, medications, insect stings, genetics, stress

Question 3

What are the general presenting symptoms of an allergic disorder?

Answer 3

Allergy symptoms include sneezing, wheezing and itchy eyes. A life-threatening allergic reaction can also cause swelling and breathing difficulties. 

Question 4

What are some common symptoms of hay fever?

Answer 4

a.k.a allergic rhinitis:
- Sneezing 
- Itching of the nose, eyes or roof of the mouth 
- Runny, stuffy nose 
- Watery, red or swollen eyes (conjunctivitis) 

Question 5

What are some common symptoms of food allergies?

Answer 5

• Tingling in the mouth 
• Swelling of the lips, tongue, face or throat 
• Hives 
• Anaphylaxis

Question 6

What are some common symptoms of an insect sting allergy?

Answer 6

• A large area of swelling (edema) at the sting site 
• Itching or hives all over the body 
• Cough, chest tightness, wheezing or shortness of breath 
• Anaphylaxis 

Question 7

What are some common symptoms of a drug allergy?

Answer 7

• Hives 
• Itchy skin 
• Rash 
• Facial swelling 
• Wheezing 
• Anaphylaxis 

Question 8

What are some common symptoms of atopic dermatitis?

Answer 8

a.k.a eczema:
- Itch 
- Redden 
- Flake or peel 

Question 9

What investigations are used to diagnose/ manage allergic disorders?

Answer 9

1. Skin Prick Testing → most commonly used test as easy to perform and inexpensive. For type I hypersensitivity reactions (IgE mediated) that cause systemic reaction.
2. Scratch Testing → used for contact dermatitis. For skin reactions (type IV hypersensitivity reaction, not IgE mediated).
3. Blood Testing → measure concentration of specific IgE antibodies in the blood
4. Serum Tryptase → specific marker of mast cell activation

Question 10

How are allergy disorders managed?

Answer 10

1. Antihistamines → cetirizine
2. Glucocorticoids
3. Emergency → adrenaline auto-injectors for self-treatment
4. Allergen Immunotherapy

Question 11

What are some complications that may arise from allergy disorders?

Answer 11

• Anaphylaxis
• Asthma
• Sinusitis and infections of the ears or lungs