CSIM 1.47 Allergic Disease 2 Flashcards
What order of insects causes allergic reactions?
Hymenoptera • Yellow jacket • Honeybee • Paper wasp • Hornet • Fire ant
What two manifestations of allergic reaction can occur with stings from Hymenoptera?
- Localised
* Systemic
What are the types of adverse reactions that can occur to medial gloves/rubber
- Irritant contact dermatitis (non-immune mediated)
- Allergic contact (type 4 hypersensitivity)
- Contact urticaria
- Rhinitis and asthma (if proteins inhaled)
- Anaphylaxis
Immune mediated allergy to rubber is caused by what? What type of hypersensitivity reaction causes each?
- Allergy to the natural latex sap (type 1)
* Allergy to chemicals used int the manufacturing process (type 4)
What are the risk group for latex allergy?
- Rubber-industry workers
- HCPs
- Those with many medial/surgical procedures
- Those with a history of food allergies
- SPINA BIFIDA
What are the mechanisms of non-immune mediated adverse food reactions?
- Metabolic
- Pharmacologic
- Toxic
- Idiopathic
What food produces a non-immune mediated pharmacological adverse reaction?
- Caffeine
- Alcohol
- Salicylates
What causes food intolerance? Give examples
Enzyme deficiencies
• Lactose intolerance
• Favism (G6PD deficiency)
Describe Favism
Haemolytic anaemia resulting from exposure to fava beans
What are ‘the big 8’?
Which of these are often outgrown, and which are persistent?
The foodstuffs responsible for 90% of the IgE-mediated food allergies:
Children: • Milk • Eggs • Wheat • Soya
Persistent: • Fish • Crustacean shellfish • Tree nuts • Peanuts
How can tolerance to egg be encouraged in intolerant children?
Encourage the child to eat baked eggs (e.g. cake)
What are the IgE-mediated allergy investigations?
Skin prick tests
• A small amount of allergen is placed onto the skin, and the skin is pricked at that site, allowing the allergen to enter the body.
• The development of urticaria wheel over 3mm is a positive result
Blood tests for specific IgE
• Solid phase with allergen attached is placed with blood sample
• A fluorescent anti-IgE is added to the solution, which binds to the IgE.
• In positive result, the IgE will bind to the allergen, thus clustering the fluorescent anti-IgE at that site
Food challenge
• Very small sample of the allergen is placed on the lower oral mucosa in ahospital mucosa
• If this is tolerated, a larger amount is used, and so on, with 15-30 mins between doses
• Failed challenge is if hypersensitivity occurs
• Monitor for 60 minutes after the challenge
Describe coeliac disease
T-cell mediated hypersensitivity reaction (type 4)
• Hypersensitivity to gluten
• Causes enteropathy in the small intestine
• T-cell mediated response causes loss of normal villi in the mucosa of the small intestine
• This reduces the surface area of the absorptive layer, resulting in malnutrition and iron deficiency anaemia in women
What is eosinophilic esophagitis
How is this diagnosed?
Mixed IgE and non-IgE mediated hypersensitivity reaction involving eosinophils and causing swallowing difficulty in response to food allergy
Diagnosed with endoscopy and biopsy - measure number of eosinophils - over 15 per high-powered field
How is non-IgE-mediated food allergy investigated?
By process of elimination, remove one foodstuff at a time until symptoms disappear
