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HYPERSENSITIVITY
OR ALLERGY
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Is an increased or excessive response to the
presence of an antigen ( foreign protein or
allergen) to which the client has been
previously exposed.
Initial responses:
ItchingWatery eyes
sneezing
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Leads to life-threatening conditions such as:
Allegric asthma
Anaphylaxis
Bronchoconstriction or
Circulatory collapse
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BASIC TYPES
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TYPE 1 HYPERSENSITIVITY
REACTION
Anaphylactic hypersensitivity
ORGAN SPECIFIC
The most severe form of hypersensitivity
reaction
The most severe immune-mediated
reaction
results from the increased production of the IgE antibody class
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Signs and symptoms:
ANAPHYLAXIS:
Uneasiness
Apprehension
Weakness
Impending doom
ALLERGIC RHINITIS:Runny nose watery eyes
Itching fever
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BRONCHIAL ASTHMA
Dyspnea wheezing
ATOPIC ECZEMA/ DERMATITIS
Urticaria angioedema
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CLINICAL EXAMPLES
Hay fever
Allergic asthma
Anaphylaxis
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TYPE II: CYTOTOXIC
REACTIONS
ORGAN SPECIFIC
May affect variety of organs and tisssues
Reaction time is 10 to 14 mins.
Primarily mediated by antibodies of Ig M and
Ig G classes and phagocyte as well as T cells
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Signs and symptoms
Fever Nausea
CIRCULATORY OVERLOAD
Dyspnea headache tachypnea
Cough chest tightness
SEPSIS
Fever nausea vomiting diarrhea
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Treatment
Autologous transfusion
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CLINICAL EXAMPLES
Autoimmune hemolytic anemia
Good Pastures Syndrome
Myasthenia Gravis
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TYPE III: IMMUNE MEDIATED
HR
NON-ORGAN SPECIFIC
May be general (serum sickness), may involve
individual organs including skin (Systemic
Lupus Erythematosus), kidneys (nephritis),lung (aspergillosis), blood vessels
(polyarthritis), joints (arthralgia, athritis/
rheumatoid arthritis)
Reaction may take 3-10 hours after exposure
of the antigen
Mediated by Ig G and Ig M
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Signs and symptoms:
Urticaria
Joint pain
Fever
Rash
Adenopathy (swollen glands)
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Treatment
-symptomatic treatment
Antihistamines- for
itchingAspirin- for athralgia
Prednisone- for severesymptoms
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CLINICAL EXAMPLES
Serum sickness
Vasculitis
Systemic Lupus Erythematosus
Rheumatoid arthritis
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TYPE IV : T- CELL MEDIATED
HR
ORGAN SPECIFIC
Delayed Hypersensitivity reaction
Mediated by T cells rather than antobodies
Lesions are more papular
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CLINICAL EXAMPLES
Poison ivy
Graft rejection
Positive TB skin tests
Sarcoidosis
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TYPE V: STIMULATORY
REACTIONS
- B cell Mediated HR
This type of reaction involves inappropriate
type of hyperthyroidism, results from excessive
output of thyroid hormones caused byabnormal stimulation of thyroid glands by
circulating immunoglobulins.
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CLINICAL EXAMPLES
Graves disease
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Signs and symptoms
Exophthalmos
Palpitations
Abnormal increased pulse
Pruritus
perspiration
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Treatment
Antithyroid agents
Radioactive iodine
surgery
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Diagnostic Evaluation
Blood tests
Smears of body secretions
Skin tests
Radioallergosorbent test (RAST)
CBC differential
Eosinophil count
Total serum Ig E levels
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