Allergy as a drug target Flashcards
What is an allergy?
A hypersensitivity reaction initiated by immunological mechanisms, the adaptive immune response to an allergen.
What is anaphylaxis?
A severe systemic allergic reaction.
can be life threatening
What is sensitivity?
The exaggeration of the normal effects of a substance. This happens gradually but isn’t life threatening.
For example caffeine in coffee can cause symptoms such as palpitations and trembling.
what is intolerance?
When a substance causes unpleasant symptoms, such as diarrhoea but doesn’t involve the immune system
List examples of allergies:
Allergic rhinitis Eczema Anaphylaxis Asthma Drug Allergy
How many types of hypersensitivity are there?
four types of hypersensitivity
What is atopy?
The genetic predisposition to developing allergic responses.
Its usually genetic
What are the 2 types of antihistamines used to treat mild allergies?
Sedating antihistamines
Non-sedating antihistamines
Give examples of a non-sedating antihistamine.
Loratadine = Inverse agonist of H1 receptor Cetrizine = Selective inhibition of H1 receptors
Give an of example of a sedating histamine.
Chlorphenamine = An inverse agonist to the H1 receptor, blocking the action of the endogenous histamine
What are the symptoms of anaphylaxis?
Tachycardia Vasodilation Hypotension Urticaria Facial swelling Angioedema (swelling) of mouth and lips Bronchoconstricition
What is the assessing pneumonic used in an anaphylactic reaction?
A B C D E
What is an epi-pen?
Epinephrine autoinjector is used during an allergic reaction. Contains adrenaline that causes vasoconstriction and opens the airways
How can an allergy be diagnosed?
Skin prick test
Lab testing
What does A stand for in the ABCDE pneumonic?
Airways
Examine for airway noises, fluid, secretions and odeoma
What does B stand for in the ABCDE pneumonic?
Breathing
Respiratory rate and oxygen saturarion
What does C stand for in the ABCDE pneumonic?
Circulation
Heart rate and Blood pressure
What does D stand for in the ABCDE pneumonic?
Disability
AVPU/GCS assessment
What does E stand for in the ABCDe pneumonic?
Exposure
Identifying and removing the possible anaphylactic triggers
What receptors does adrenaline have an effect on?
Alpha 1 - smooth muscle contraction
Alpha 2 - Inhibitor of transmitter release and smooth muscle contraction
Beta - Heart muscle contraction and smooth muscle relaxation
What is a possible long term treatment for chronic allergic symptoms/reactions?
Immunotherapy
What are the most common food allergies?
Peanuts Tree nuts Milk Eggs Wheat Soy Fish Shellfish
What are the most common drug allergies?
Penicillin
NSAID
General anaesthesia allergy
What are the possible topical treatments for allergies?
Inhalers
Creams
Eye drops
Nasal sprays
What are the possible symptoms of an allergic reaction.
Skin rash Nasal congestion Sore throat Nausea and diarrhoea Dizziness Fever
What is type 1 hypersensitivity?
Involves IgE antibody against soluble antigen which triggers mast cell degranulation.
Give examples of type 1 hypersensitivity reactions.
Anaphylaxis
Asthma
Hay-fever
What is type 2 hypersensitivity?
The Involves IgG and IgM antibodies directed against cellular antigens. Leading to cytotoxicity mediated by other immune system effectors
Give examples of type 2 hypersensitivity.
Goodpastures syndrome - antibodies attack basement membrane
Haemolytic transfusion reaction - mismatch in blood types, The body is attacked by antibodies
What is type 3 hypersensitivity?
Involves interactions of IgG, IgM and IgA antibodies with antigen to form immune complex (when they accumulate in the tissue it can cause damage)
Give an example of type 3 hypersensitivity.
Post-streptoccus glomerulonephritis
What is type 4 hypersensitivity?
T-cell mediated reactions that involve tissue damage mediated by activated macrophages and cytotoxic T cells
cell-mediated hypersensitivity
Give examples of type 4 Hypersensitivity.
Type 1 diabetes, MS, Transpant rejections
It occurs at least 48-72 hours later
