Allergy, corticosteroids and antihistamines Flashcards
Both the innate and adaptive immune system play a role in allergy. True or false?
True
What is atopy a result of?
Overproduction of TH2 cytokines in response to allergens
The innate system is responsible for catalysing the sensitisation process which leads to allergic reactions. True or false?
True
What are the 3 diagnostic tests for allergy?
Skin prick test - in vivo
Blood test - in vitro
Mast cell tryptase
Patients with atopic dermatitis have reduced skin barrier function. True or false?
True
What is the typical treatment for atopic dermatitis?
Topical corticosteroids
Why should high-potency corticosteroids only be used over short period of time, in treating atopic dermatitis?
Due to adverse effects
What is allergic rhinitis?
IgE inflammation of the nasal mucosa in response to outdoor and indoor allergens
Allergic rhinitis is a risk factor for asthma. True or false?
True
Birth by C section can increase the risk factor for allergic rhinitis. True or false?
True
Symptoms of food allergy are mediated by IgE and non-IgE reactions. True or false?
True
Angioedema can be caused by food allergy. True or false?
True
IgE mediated reactions occur within minutes to hours of ingestion of food that patient is allergic to, whereas non-IgE mediated reaction take hours to days later. True or false?
True
The health of the GIT has no influence on food allergy. True or false?
False - as it acts as a semipermeable barrier allowing only usable molecules into bloodstream after breakdown of food
Steroids and and allergy shots can be used for treatment of allergies, but what is the first line treatment?
Antihistamines
All four of histamine receptors subtypes are ligand gated ion channels. True or false?
False - GPC receptors
Only H1 and H4 are of clinical interest. True or false?
False - H1 and H2
What are the histamine physiological effects that are mediated by H1 receptors?
Contraction of bronchial smooth muscle Contraction of intestinal smooth muscle Stimulation of sensory nerve endings Enhancement of Ca2+ influx into cardiac myocytes leading to minor increases in inotropism and chronotropism Increased production of nasal mucus
What effect does activation of H2 receptors have?
Potentiation of gastrin induced acid secretion
H1 receptor antagonists block the action of histamine. They are also potent at H2 receptors. True or false?
False - no potency at H2 so don’t affect gastric acid secretion
H2 blockers block histamine2 which is a producer of acid. True or false?
True
What are the benefits of antihistamines?
Decreased histamine release
Decreased inflammation
Decreased antigen presentation
What are the negative effects of antihistamines?
Decrease neurotransmission in CNS
Dry mouth
Hypotension, dizziness, reflex tachycardia
Increased sedation
What are glucocorticoids?
Steroids synthesised in the adrenal cortex
Glucorticoids inhibit cell-mediated immunity. True or false?
True
What are the cytokines that are inhibited by glucorticoids?
IL1-6 and IL8
What are the side effects of glucorticoids?
hyperglycaemia
poor wound healing
use in children can lead to growth retardation
Inhibition of which cytokine by glucorticoids has the most crucial effect in immunosuppression?
IL2 - inhibits proliferation of Tcells and activation of cytotoxic T cells