ALLERGY AND ANAPHYLAXIS Flashcards
What percentage of children have some form of allergy in the UK?
Up to 40%
What are the most common allergens?
Inhaled:
House-dust mite, plant pollens, pet dander, moulds
Ingested:
Nuts, seeds, legumes, cow’s milk, eggs, seafood and some fruits
Insect stings/bites
Drugs
Latex
What types of allergic reaction occur?
Eczema
Allergic rhinitis and conjunctivitis
Urticaria
Anaphylaxis
How do we classify allergic immune responses?
IgE related - occurs within minutes
Non-IgE related - occurs after 4-6 hours
What are the clinical features of allergy?
Mouth breathing
Allergic salute - from rubbing an itchy nose
Pale and swollen inferior nasal turbinates
Hyperinflated chest or Harrison sulci from chronic undertreated asthma
Atopic eczema in limb flexures
Allergic conjunctivitis
Failure to thrive
What is the difference between allergy and intolerance?
Allergy is immune modulated whereas intolerance is not
What are the most common food allergies in infants?
Milk
Eggs
Peanuts
What are the most common food allergies in older children?
Peanut
Tree nut
Fish
Shellfish
What is a secondary food allergy?
Where children initially tolerate a food and then become allergic to it. This is usually due to cross reactivity between proteins present in fruits and pollens. Eg apples and birch tree pollen.
What are the clinical features of IgE mediated food allergy?
Urticaria
Facial swelling
Anaphylaxis
What are the clinical features of non-IgE mediated food allergy?
Diarrhoea
Vomiting
Abdominal pain
Failure to thrive
Blood in stools in neonates (due to proctitis)
How is the diagnosis of food allergy made?
- Skin prick test and measurement of specific IgE antibodies in blood (RAST test)
Gold standard – Exclusion of relevant food under a dietician’s supervision, followed by double blind placebo controlled challenge. Must be performed in hospital.
What are the three drugs used in the emergency treatment of anaphylaxis?
Adrenaline
Hydrocortisone
Chlorphenamine
What dose of adrenaline would be given to an infant of less than 6 months in anaphylaxis?
150 micrograms (15ml of 1 in 1000)
What dose of hydrocortisone would be given to an infant of less than 6 months in anaphylaxis?
25 mg
What dose of chlorphenamine would be given to an infant of less than 6 months in anaphylaxis?
250 micrograms/kg
What dose of adrenaline would be given to a child of less than 6 years old in anaphylaxis?
150 micrograms (15ml of 1 in 1000)
What dose of hydrocortisone would be given to a child of less than 6 years but older than 6 months in anaphylaxis?
50 mg
What dose of chlorphenamine would be given to a child of less than 6 years but older than 6 months in anaphylaxis?
2.5 mg
What dose of adrenaline would be given to a child of 6-12 years of age in anaphylaxis?
300 micrograms (30ml of 1 in 1000)
What dose of hydrocortisone would be given to a child of 6-12 years of age in anaphylaxis?
100 mg
What dose of chlorphenamine would be given to a child of 6-12 years of age in anaphylaxis?
5 mg
What dose of adrenaline would be given to a child older than 12 years of age in anaphylaxis?
500 micrograms (50ml of 1 in 1000)
What dose of hydrocortisone would be given to a child older than 12 years of age in anaphylaxis?
200 mg
What dose of chlorphenamine would be given to a child older than 12 years of age in anaphylaxis?
10 mg
A 12-year-old girl is admitted to the Emergency Department following a suspected peanut allergy. On examination she has gross facial and tongue oedema. Her oxygen saturations are 97% on room air, pulse is 110 / min and blood pressure is 90/62 mmHg. The paramedics have already gained intravenous access. What is the most appropriate way to give adrenaline in this situation?
The Resuscitation Council guidelines only recommend giving adrenaline intramuscularly, regardless of whether the patient has intravenous access or not.
What is the best site for an IM adrenaline injection to treat anaphylaxis?
Anterolateral aspect of middle third of the thigh
How often can IM adrenaline injection be repeated in anaphylaxis?
Every 5 minutes
