ALLERGIC DISEASES

Question 1

Allergy & Hypersensitivity

Answer 1

Undesirable, damaging, discomfort-producing and sometimes fatal reactions produced by the normal immune system (directed against innocuous antigens) in a pre-sensitized (immune) host.

Question 2

Type 1 anaphylactic

Answer 2

IGE. 30 mins. Basophils and eosinophils. E.g. allergic asthma

Question 3

Type 2 cytotoxic

Answer 3

: IGG, IGM. 1 hour. Antibody and complement. E.g goodpastures nephritis

Question 4

Type 3 immune complex

Answer 4

igG, igM, 3-8 hours, complement and neutrophils. Hay farmers lung.
Eg SLE.
SOLUBLE ANTIGEN- Traditional cause of serum sickness

Question 5

Type 4 delayed.

Answer 5

No ab. Up to 72 hours. Monocytes lymphoctes and T cells. E.g. Contact dermatitis

Question 6

Immune responses to parasitic disease

Answer 6

Increased levels of IgE in Total and Specific to pathogen: cross-reactive
Tissue inflammation with: eosinophilia & mastocytosis and Basophil infiltration
Presence of CD4+ T cells secreting: IL4, IL5 & IL13

Question 7

tests available for allergic diseases

Answer 7

History
Specific IgE (>0.35 KuA/L)- Produced false N/P
Skin prick test (>3mm wheal): quick, patient satisfaction, fp/fn. risk.
Intra-dermal test
Oral challenge test – Gold standard
Basophil activation test
Component resolved diagnostics

Question 8

atopic triad

Answer 8

Asthma, atopic dermatitis (eczema) and allergic rhinitis

Question 9

RHINITIS

Answer 9

Allergic - perennial or seasonal.
Blocked nose, runny nose - often with eye symptoms. House dust mite, animal danders, pollens.
Treatment – Antihistamines & Nasal steroids

Question 10

ASTHMA

Answer 10

Disease of inflammation: hyper-reactivity of small airways in childhood.
Aero-allergic stimuli: house dust mite key pathogenic importance.
Immediate symptoms are igE-mediated. damage to airways due to late phase response, damaged airways are hyper-reactive to non-allergic stimuli e.g. fumes.

Question 11

ATOPIC DERMATITIS:

Answer 11

CONTACT - ALLERGIC/NON-ALLERGIC. CLINICALLY - Intense itching, blistering/weeping, cracking of skin. HOUSE DUST MITE now thought to be MAJOR TRIGGER in atopic disease.
Topical Steroids & Moisturisers

Question 12

MAJOR FOOD ALLERGENS

Answer 12

• Water soluble glycoproteins 10 - 60 kd
• COW’S MILK
• EGG
• LEGUMES - PEANUT; SOYBEAN; TREE NUTS
• FISH
• CRUSTACEANS / MOLLUSCS
• CEREAL GRAINS

Question 13

Clinical manifestations of drug and food allergy

Answer 13

Gastrointestinal: vomiting, diarrhoea, oral symptoms
Respiratory (upper & lower): rhinitis, bronchospasm
Cutaneous: urticaria, angioedema, role of food in atopic dermatitis unclear
Anaphylaxis

Question 14

reaction to drugs

Answer 14

E.g Beta lactam antibiotics such as penicillin. IgE mediated. Can manifest as bronchospasm or anaphylaxis.