Ch 15 Allergy

Question 1

The allergic march: allergic children develop individual allergic disorders at different ages: Infancy (2), Pre-school/primary school (3)

Answer 1

Infancy - food allergy + eczema

School - allergic rhinitis + conjunctivitis > asthma

Question 2

History & examination features of allergic child (5)

Answer 2

mouth breathing - obstructed nasal airway
Allergic salute - from rubbing nose
Nasal turbinates - pale and swollen
Hyperinflated chest
Atopic eczema - flexural
allergic conjuncitivitis - also prominent creases (Dennie-Morgan folds) + blue-grey discolouration below lower eyelids

Question 3

Mechanism of: food allergy (IgE vs non IgE mediated) food intolerance, oral allergy syndrome

Answer 3

Food allergy - IgE mediated; 10-15 min post ingestion, non-IgE mediated; hours post ingestion
Food intolerance - non-immunological hypersensitivity rxn
Oral allergy syndrome - secondary food allergy due to cross reactivity between fruit/veg/nut proteins and pollen protein

Question 4

Causes of food allergy/intolerance: (5)

Answer 4

Infants - milk, egg, peanut

Older children - peanut, tree nut, fish, shell fish

Question 5

Features of IgE mediated food allergy (3), non IgE mediated food allergy (3)

Answer 5

IgE mediated: Urticaria, facial swelling, anaphylaxis 10-15 min post ingestion
Non IgE mediated: GI symptoms - D&V, abdo pain, FTT, blood in stool

Question 6

Diagnosis of food allergy/ intolerance: (3)

Answer 6

Skin prick test
RAST - measures specific IgE in blood
Double-blind placebo-controlled Food challenge

Question 7

Management of mild rxns (1), severe rxns (1)

Answer 7

Generally avoid relevant foods
Mild rxns - anti histamines e.g. chlorphenamine
Severe rxns - IM adrenaline

Question 8

Allergic rhinitis: features (4), management (4)

Answer 8

Can be atopic (IgE) non-atopic (IgE mediated)
F - coryza + conjunctivitis + cough variant + chronic blocked nose
M - non-sedating antihistamines, topical corticosteroids, cromoglycate eye drops, nasal decongestants, allergen immunotherapy (sublingual)

Question 9

Acute urticaria: cause (2), features (2)

Answer 9

Resolves within 6 weeks
C - viral infection/ allergen > allergic skin rxn (weals- raised itchy rash on skin)
F - angioedema, anaphylaxis

Question 10

Chronic urticaria: causes (1), management (1)

Answer 10

C - usually non allergic via mast cells

M - non sedating anti histamines e.g. cetririzine

Question 11

Drug allergy - how to confirm (1)

Answer 11

Drugs are often blamed when it is not the case e.g. roseola infantum
Drug challenge only way to confirm