Allergies
It is the overproduction of IgE Allergy - Any exaggerated immune
antibodies in response to otherwise response to substances common in
innocuous environmental antigens the environment that are usually
that cause allergies. harmless to other people.
Certain causes are
UNDETERMINED
Atopy - A genetically determined
state that leads to an exaggerated Rhinitis:
IgE-mediated immune response. Most prevalent
All atopic
disorders are respiratory disease.
type I Nasal itching, blockage,
hypersensitivi rhinorrea and frequent
Urticaria & Angioedema: Eczema: sneezing.
ty disorders.
Raised itchy battle rash (hives). Local erythematous inflammation Often linked with Nose running
Usually triggered by food and drug of the skin. asthma.
allergens. Often appears in early chill induced
by food such as eggs and milk.
NSAIDS & Asthma:
ACE Inhibitors Chronic disorder of airways with
Adrenaline
injection variable airflow limitation.
Diagnosis: Throughout entire Recurrent episodes of wheeze,
Type of symptoms body breathlessness, chest tightness and
Time of onset Anaphylaxis - A systemic cough.
Frequency and duration Most severe allergic immediate hypersensitivity reaction Respiratory,
characterised by oedema in many blood,
Day/night variation reaction. Allergen Sensitisation -
tissues and a decrease in blood cardiovascular,
Occurrence in relation to trigger Life-threatening and can Exposure to an allergen which
pressure secondary to vasodilation gastrointestinal
such as food, exercise drug intake result in death without leads to IgE production.
Family history of allergy prompt treatment. and vascular leak. Becomes an
Skin Prick Test: Triggered by many allergen when Antibody is trying
Relies on sensitised cells in allergens. cells are to combat the allergen
skin responding to causative Foods, drugs, venoms, latex sensitised to it
allergen leading to Cause much of
degranulation and local tissue our allergic Two main pathological events:
swelling. response Differentiation of naive T cells to
Selection of allergens to test Th2.
determine according to clinical Stimulate B cells to switch to IgE
Specific to
history. production.
the antigen Chemical/biological
Patient should not be taking
antihistamines. substances - not
Hypersensitivity- Type Detected by antigen
Histamine and saline used as invading bacteriums
of reaction where cells presenting cell and bind to
controls. become hypersensitive T cells which activate Allergen gets into dendritic cell Release factors
to an allergen. different responses. (antigen presenting cell). into environment
Binds to naive T cell and goes down which cause
Breakdown
Th2 pathway and produce inflammation
and lose
antibodies.
their Inflammation Mast Cells & Basophils:
B cells produce IgE antibodies which
contents. stops pathogen Initiate acute
learn the sequence of allergens that
spreading further inflammatory responses.
have invaded.
Mast cells are early
Promotes plasma cell production —Mast cells found in
producers of cytokines in
which produces lots of IgE that bind connective tissue
Cause inflammation response to infection/
Key Granule Contents: to mast cells so it’s ready to respond surrounding blood vessels
Stages of Allergy: when released, causing injury.
Histamine to the pathogen. and mucosal surfaces.
constriction of muscles, Leukotrienes Bind facing outward
—Basophils reside in the
causing more immune Neutrophil & eosinophil Great for Movement of so it’s ready for the
circulation.
activation. attracting chemokines infection the stomach allergen/antigen
Inflammatory cytokines Bad in allergies,
good for allergens
Phases of Allergic Response: Due to:
Early Mucus production
-Physiological mechanisms CD4 T Cell - Helper
Vasodilation and
-Loss of organ functions lymphocyte which
swelling
Phases of Allergy: Late helps B cells to produce
Bronchoconstriction
Immediate -Immunological mechanisms antibodies.
-Mast cell degranulation -Recruitment of immune cell into peripheral
IL-4 - Cytokine which
-Histamine release tissues
promotes Th2 T cells and
Late -Smooth muscle scarring
IgE production by B cells.
-Immune response
-Eosinophil migration Eosinophil - Innate
immune cell found in
the blood which migrates
Autoimmune Disorders -
into tissues and mediate
Clinical When the immune system
late phase reaction.
Consequence of mistakes friend for foe
Late Phase: and attacks our own
bodies.
Symptoms of Allergies:
Sneezing
Runny/blocked nose
Red, itchy, watery eyes
Wheezing/coughing
Allergic responses Red, itchy rash
becoming more Worsening of asthma/eczema
common symptoms
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