L8 asthma and allergy Flashcards
how to antihistamines work
Antihistamines block the effects of a substance called histamine in your body. Histamine is normally released when your body detects something harmful, such as an infection. It causes blood vessels to expand and the skin to swell, which helps protect the body.
what is an allergy
a damaging immune response by body to a substance which it has become hypersensitive
3 things included in atopy
atopic dermatitis
asthma
allergic rhinitis - hay fever
an antibody is made heavy chain ( inside top) and light chains( outside top) the fab region is found at the top of the antibody an the Fc region is find where
bottom part of the antibody with the FcRI binding sites
allergen activates ..... to the dendritic cell which then presents this to naive T cells using its TCR( receptors) mediated by the interleukin .... this then differnteites into Th2 cells and clonal expansion - class switching of TH2 cells by Il4 and Il13 to either B cell memory or plasma cells
MHC2
IL4
Il4 induced B cell class swichitn o IGE production and opposes Th1 activity what does IL5 do
esooniophil growth factor
what does IL13 do
acts on epithelial cells and smooth muscle
IL17 enhances eosinophil recruitment what does IFNgamma do released by Th1
inhibits switch to IGE
as we know Th2 cell involved in allergic disease and TH1 is involved in intracellular MOs as well as autoimmunity what is Th17
extracellular bacteria and fungi as well as autoimmunity
what are the mast cell mediators and what do they do
biogenic amines such as histamine causing vasodilation and vascular leak
lipid mediators causing brnchoconstriction and intestinal hyper motility
cytokines causing inflammation
enzymes such as tryptase causing tissue damage
Ige mediated food reactions symptoms
onset under 60 mins erythema , urticaria , angioedema vomiting and diarrhoea. and cramps cough sneezing and stridor and wheeze as well as a hoarse voice hypotension
if non- Ige mediated up to 48hr and weight loss and abdomen pain with hypotension
what do you give to someone having an allergic reaction
adrenaline - alpha and beta agonist actions resulting in vasoconstriction and reversal of bronchoconstriction and reduction in the volume of inflammatory mediators
Symptomatic treatment – antihistamines, salbutamol, fluids and steroids
anaphylaxis is highly likely when
respiratory compromise present- stridor , wheeze hypoxemia
reduced BP or associated symptoms of end organ dysfunction
new treatment using monoclonal antibodies what can you give
Omalizumab – binds to fre iGE – decreased allergic inflammation also for astgam for adults
new treatment using monoclonal antibodies what can you give
Omalizumab – binds to fre iGE – decreased allergic inflammation also for astgam for adults
