Paediatrics- Allergy Flashcards
What is the definition of hypersensitivity?
Objectively reproducible symptoms or signs following exposure to a defined stimulus (e.g. food, pollen, drugs) at a dose which is usually tolerated by most people
What is the definition of allergy?
A hypersensitivity reaction initiated by specific immunological mechanisms. Can be IgE mediated (e.g. peanut allergy) or non-IgE mediated (e.g. coeliac disease)
What is the definition of atopy?
A personal and/or familial tendency to produce IgE antibodies in response to ordinary exposures to potential allergens, usually proteins. Strongly associated with eczema, asthma, food allergy, allergic rhinitis, and conjunctivitis
What is the definition of anaphylaxis?
A serious allergic reaction with bronchial, laryngeal, or cardiovascular involvement that is rapid in onset and may cause death
Allergic immune responses can be classified into what two categories?
IgE mediated and non-IgE mediated
What is the characteristic clinical course of IgE mediated reactions?
1) Early phase: minutes after exposure, caused by release of histamine and other mediators from mast cells –> urticaria, angioedema, sneezing
2) Late phase: 4-6 hours after exposure, especially when inhaled allergens –> nasal congestion in the upper airway, and cough and bronchospasm in the lower airway
What is the allergic march?
Allergic children develop individual allergic disorders at different stages:
Infancy: eczema and food allergy
Primary school age: rhinitis, conjunctivitis, asthma
The presence of eczema and food allergy in infancy is predictive of asthma and allergic rhinitis in later life
Food allergy/intolerance: what are the clinical features of the IgE-mediated response?
1) Urticaria
2) Facial swelling
3) Anaphylaxis
4) Usually occurs 10-15 minutes after eating
Food allergy/intolerance: what are the clinical features of the non-IgE mediated response?
Diarrhoea, vomiting, abdominal pain
Faltering growth, colic, eczema (less common)
How is food allergy diagnosed?
IgE mediated: skin prick tests and measurement of specific IgE antibodies in blood (RAST)
Non-IgE mediated: more difficult- clinical history and examination (maybe endoscopy)
How is food allergy diagnosed in cases of doubt?
Exclusion of relevant food under supervision, followed by a double-blind placebo-controlled food challenge
How is food allergy managed?
1) Avoid relevant foods
2) Training on how to manage allergic attack
3) Severe reaction: epinephrine given IM by auto-injector
What are the common food allergies of childhood?
Cow’s milk, egg (often resolves in childhood)
Nuts and seafood (usually persists into adulthood)
Wheat, seeds, fruit, legumes
What is rhinoconjunctivitis classified as?
Intermittent or persistent
Seasonal or perennial
What is the classic presentation of rhinoconjunctivitis?
coryza and conjunctivitis
