Allergy

Question 1

What are some examples of allergic disease which affect children?

Answer 1

food allergy, eczema, allergic rhinitis and conjunctivitis, asthma, urticaria, insect sting hypersensitivity and anaphylaxis

Question 2

What is hypersensitivity?

Answer 2

Objectively reproducible symptoms or signs following exposure to a defined stimulus (e.g. food, drug, pollen) at a dose which is tolerated by normal people

Question 3

What is an allergy?

Answer 3

A hypersensitivity reaction initiated by specific immunological mechanisms. This can be IgE mediated (peanut allergy) or non-IgE mediated (coeliac disease)

Question 4

What is atopy?

Answer 4

A personal and/or familial tendency to produce IgE antibodies in response to ordinary exposures to potential allergens, usually proteins. Strongly associated with asthma, allergic rhinitis and conjunctivitis, eczema and food allergy

Question 5

What is anaphylaxis?

Answer 5

A serious allergic reaction that is rapid in onset and may cause death

Question 6

What is the early phase of an IgE mediated reaction?

Answer 6

An early phase, occurring within minutes of exposure to the allergen, caused by the release of histamine and other mediators from mast cells. Causes urticaria, angioedema, sneezing and bronchospasm

Question 7

What is the late phase of at IgE mediated reaction?

Answer 7

Occurs 4-6 hours after event. This causes nasal congestion in the upper airway, and cough and bronchospasm in the lower airway

Question 8

When do eczema and food allergy usually present?

Answer 8

Usually during infancy, both are often present

Question 9

When does allergic rhinitis and conjunctivitis and asthma usually present?

Answer 9

Most often in preschool and primary school years

Question 10

When does rhinitis and conjunctivitis usually present?

Answer 10

Often preceded the development of asthma, and in children with asthma, up to 80% have coexistent rhinitis

Question 11

What might you find on examination of an allergy?

Answer 11

Mouth breathing
An allergic sault, from rubbing an itchy nose
Pale and swollen inferior nasal turbinates
Hyperinflated chest of Harrison sulci from chronic untreated asthma
Atopic eczema affecting the limb flexures
Allergic conjunctivitis

Question 12

How does specific allergen immunotherapy work?

Answer 12

Solutions of an allergy are injected subcutaneously or administered sublingually on a regular basis for 3-5 years, with the aim of developing immune tolerance

Question 13

What are the most common food allergies?

Answer 13

Infants: milk, egg, peanut

Older children: peanut, tree nut and fish and shellfish

Question 14

What are the clinical features of an IgE mediated food allergy?

Answer 14

History of allergic symptoms varying from urticaria to facial swelling to anaphylaxis, usually occurring 10-15 mins after ingestion of a food.

Question 15

How does a non-IgE mediated food allergy typically present?

Answer 15

Diarrhoea, vomiting, abdominal pain and sometimes failure to thrive. Colic or eczema may also be present

Question 16

How would you diagnose a food allergy?

Answer 16

IgE-mediated: skin prick test and measurement of specific IgE antibodies in blood (RAST test)
Non-IgE mediated: history, examination, possible endoscopy and intestinal biopsy

Question 17

How would you manage a food allergy?

Answer 17

Exclude the said food from diet, with help from a paediatric dietician. In acute situations, mild needs antihistamines, severe needs adrenaline IM injection

Question 18

Which allergies usually persist into adulthood and which don’t?

Answer 18

Cows milk and eggs often resolve in early childhood; nuts and seafood usually persist through to adulthood

Question 19

How can allergic rhinitis and conjunctivitis present?

Answer 19

In addition to its classic presentation of coryza and conjunctivitis, it can also present as ‘cough-variant rhinitis’ due to a post-nasal drip, as a chronically blocked nose causing sleep disturbance and impaired daytime behaviour and concentration, or with predominant eye symptoms

Question 20

How would you treat allergic rhinitis and conjunctivitis?

Answer 20

Antihistamines, topical corticosteroid nasal or eye preparations, eye drops, nasal decongestants

Question 21

What causes acute urticaria?

Answer 21

Acute urticaria usually results from exposure to an allergen or a viral infection, which triggers an urticarial skin reaction.

Question 22

Alongside the skin, what else might urticaria effect?

Answer 22

It may also involve deeper tissues to produce swelling of the lips and soft tissues around the eyes (angioedema) and even anaphylaxis

Question 23

What causes chronic urticaria?

Answer 23

It is usually non-allergic in origin and results from a local increase in the permeability of capillaries and venules.

Question 24

How would you treat chronic urticaria?

Answer 24

Second-generation non-sedating antihistamines

Question 25

What are some causes of physical urticaria?

Answer 25

Cold, delayed pressure, heat contact, solar, water, sweating, aspirin and other NSAIDs