Allergic Reaction: Overview
• Allergy
– Inappropriate, often harmful response to a normally harmless substance
• Atopy
– Genetic predisposition to allergic rxns.(Ex: Seasonal allergies
• Rise in IgE and Esinophils
• Antigen
– Foreign invaders. (ex: Pet Dander, peanuts)
• Antibody
– Attacks the antigen
Function of IgE
• Bind with… Antigens. This triggers the mast cell “Water balloon of chemical mediators (ex:
histamine, leukotrienes)”
– Will see skin reactions, whelps, Diff breathing, Laryg Edema, hives, rashes
• Trigger…
• Release chemical mediators
• Disorders
Reference pg1860
• Antigen B-Cells
IgE binds
Antigen
• Stimulates release  to mast cells  binds to
• B-Cell
IgE
IgE
Chemical Mediators
• Released from stimulated mast cells
• Trigger sequence of events resulting in symptoms
• 2 types
– Primary Mediators
– Secondary Mediators
Primary Mediators, Pharm Chap 69
• Histamine
– Effects: Edema, Airways, Bronchi, Laryngeal edema, Itching, redness of skin, Mucosa
membranes eye/nose (weeping of tissues in general)
– Maximum amount of intensity is w/in 15min of contact w/ antigen
– Constriction of bronchioles
– Dilation of small vessels & constriction of core vessels
– Two types:
*H1 receptors- bronchiolar and vascular smooth muscle cells. Activation of H1 receptors causes
dilation of small blood vessels. Incr capillary permeability. Bronchoconstriction. Itching/Pain.
Mucous secretion.
(ex: Benadryl)
*H2 receptors- gastric parietal cells. Activation of H2 receptors is secretion of gastric acid.
Allergic responses. Histamine release. Severe = Anaphylaxis, (treat: epinephrine).
(ex: Zantac, pepcids)
Other Primary Mediators
• Eosinophil Chemotactic factor
– Eosinophils- They incr in number with allergy and parasitic conditions and decr w/
steroid administration. Larger than Neutrophils.
• Platelet aggregating factor
• Prostaglandins (Will cause the inflammation along w/ fever and pain)
Secondary Mediators
released in response to a primary
• Each causes smooth muscle contraction & increased vascular permeability
• Leukotrienes- responsible for the inflammatory response (responsible for wheals/whelps in skin)
• Serotonin- Vasoconstrictor
• Bradykinin- responsible for muscous production
Hypersensitivity – 4 types
• Type I – Anaphylatic
• Type II – Cytotoxic
• Type III - Immune Complex
• Type IV - Delayed
Type I - Anaphylactic
• Most severe form of hypersensitivity
• Characterized by edema in many tissues & hypotension
• Begins within minutes, mediated by IgE antibodies (if no increase in IgE than its not
Anaphylactic Reaction)
• Type 1 is a TRUE ALLERGY
• Severity depends on exposure, amount of allergens, sensitivity of target organs, and route of
allergen exposure.
• Requires previous exposure
Examples of Type I Reactions
• Extrinsic asthma- outside source, ex: pet dander
• Allergic rhinitis
• Systemic anaphylaxis
• Insect sting reactions
• Vasodilation in extremities, incr capillary permeability, smooth M Contraction, and high levels of
eosinophils.
Type II or Cytotoxic
• Body attacks self- cytotoxic- related to compliment cascade. Ex (Mgravis, blood transfusion
reactions)
• IgG or IgM antibody
• Activation of complement cascade
• Cell destructionType III or Immune Complex
• Involves IMMUNE COMPLEXES, when antibody binds w/ antigen. They don’t break down the
way they should and form slusters leading to…
• Phagocytosis- tissue damage.
• Injury due to
– ↑Circulating complexes & Vasoactive amines
– ↑ vascular permeability & tissue injury.
– Joint & kidneys
Type III or Immune Complex
• Systemic Lupus Erythematosus (SLE)
• Rheumatoid Arthritis
• Nephritis
• Bacterial Endocarditis
Type IV Delayed Hypersensitivity
Non- Atopic reactions, so no incr in IgE or Eosinophil levels
•
•
Occurs 24-72 hrs after exposure
Examples
– TB test
– Poison Ivy
– Contact dermatitis (tape, topical medications, cosmetics)
• S/S = Itching, erythema, raised lesions
Nursing Care of Hypersensitivity
See Chart 53-7, pg 1876
Assessment
• History
• Physical assessment
Diagnostic Testing
• WBC – Normal, because its antigen, not infection
• Eosinophils (granulated WBC)
• Normal 1-3%
• ^ 5-15% suggestive allergy
• ^15-40% moderate
• ^50-90% severe- Definite allergic reaction
• Eosinophil count of tissue smear
– Swab in mouth, oral, throat
Diagnostic Testing
• IgE level
– ↑ IgE levels indicate allergic disorder
• Useful in evaluation of:
– Immunodeficiency
– Drug reactions
– Atopic vs. non-atopic dermatitis, asthma, and rhinitis
Diagnostic Testing
• Skin tests
– Prick/Scratch (easiest test available)
– IntraDermal (injection of antigen INTO the skin)
• Interpretation
– Urticarial wheal, erythema, or pseudopodia “reaching outward of redness”
– Do not perform while pt has active bronchospasm
Diagnostic Testing
• Provocative testing- direct admin of allergen into target tissue.
– Only one test per visit.
• RAST (Radioallergosorbent Test)- The patient's blood is mixed with a possible allergen in a test
tube.
– The Safest cause there is no pt contact.
Allergic Disorders
• 2 types
– Atopic
• IgE & Genetic predisposition
• Allergic rhinitis
• Allergic asthma
• Atopic dermatitis
– Non-atopic
• No IgE
• No organ specificity
• No genetic link
Anaphylaxis – Type I Hypersensitivity
• Reaction of Antigen + IgE antibody
• Release of histamine, other mediators, & WBCs
– Smooth muscle spasm
– Bronchospasm
– Mucosal edema
– Inflammation
– Increased capillary permeability- fluids are seepiong into the tissue
Anaphylaxis – Type I Hypersensitivity
Clinical Manifestations
• Mild
– Tingling/ warmth,
– fullness in mouth/throat
– Nasal congestion
– Perioribital swelling
– Pruritis
– Sneezing
• Moderate
– Sx of mild rx &
• Flushing
• Warmth
• Anxiety
• Itching
Anaphylaxis Clinical Manifestations
• Severe (right amount to rt organ  Cardiac arrest = PTTP)
– Abrupt onset of previous symptoms
– Bronchospasm
– Laryngeal edema
– Severe dyspnea
– Cyanosis
– Hypotension… cardiac arrest
Management of Anaphylaxis
• Prevention
– Avoidance!!!
– Epinephrine- epi pen on hand = good. But only use when having reaction! Normal + Pen
= Cardiac arrest
– Screening for allergies
– Identification- allergy band = good
Anaphylaxis – Type I Hypersensitivity
• Medical Management
– Depends on severity
– Support Resp/Cardiac fx
• Oxygen
• Epinephrine 1:1000 SQ, then IV
• Antihistamines, Benadryl, cortisone- to decr inflammation so pt can breathe
• Iv fluids, volume expanders, vasopressors
• Possibly aminophylline or steroids
– Desensitization- commonly done for insulin, aka “Controlled anaphylaxis”
Anaphylaxis – Type I Hypersensitivity
Nursing Management
• Assess pt with allergies for s/sx anaphylaxis
• Increasing edema
• Respiratory distress
• Notify physician
• O2
• Prepare emergency meds
• Patent IV
• Document response, VS, labs
Allergic Rhinitis
• a.k.a. Hay fever- most common foorm of respiratory allergy
• Often with conjunctivitis, sinusitis, & asthma
• Complications
– Chronic nasal obstruction, polyps, or obstruction in airways
– Chronic otitis media
– Anosmia- lack of smell
Allergic Rhinitis
• HISTAMINE!!
– Tissue edema d/t vasodilation and increased capillary permeability.
Manifestations of Allergic Rhinitis….
• Nasal congestion
• Clear, watery discharge
• Sneezing
• Itching
• Dry cough
• Headache
• Sinus pain
Allergic Rhinitis
• Not a severe disease but a serious disease in that it greatly affects quality of life…
– Fatigue
– Loss of sleep
– Poor concentration
– Dry, chapped, sore skin to face
Assessment of Allergic Rhinitis
• History- how long had it, anything improves it?
• Physical Assessment
• Allergy testing
• Serum IgE levels
Management of Allergic Rhinitis
• Relieve symptoms
– Avoidance therapy
– Immunotherapy (allergy shots)- kinda like desensitization
– Pharmacotherapy
•
•
Antihistamines- Benadryl (but its sedating), so Zyrtec, Claritin
Adrenergics- stop mucosal weeping, decr edema. Short term use, else poss
Rebound Effect.
• Mast Cell Stabilizers- Nasalcrom
• Corticosteroids- Flonase, Nasonex (localized steroids)
– Education
Allergic Rhinitis: Nursing Diagnoses
• Ineffective breathing pattern
• Deficient knowledge- decongestants will raise BP
• Ineffective individual coping- inability to breath. Feels miserable.
Contact Dermatitis
• A type IV hypersensitivity
• Clinical Manifestations
– Acute or Chronic skin inflammation
– Itching
– Burning
– Skin lesions
– Edema
– Weeping, crusting, drying and peeling of skin
– Risk of secondary infection d/t scratching
• Assessment
• Four types:
– Allergic- pt is suceptible to a certain thing
– Irritant- 80% of contact dermatiitis cases
– Photoxic- chem irritant and a sun exposure
– Photoallergic- sun exposure and allergen contact
Atopic Dermatitis
An allergic contact dermatitis
• A.K.A. Eczema
• A type I sensitivity disorder.
• Common in children.
• Have dry, red, hyperirritable skin
– Extended contact could lead to severe reaction
– Treat w/ topical cream
Dermatitis Medicamentosa
• Skin rash from internal medication administration (causes BRIGHT RED RASH)
• Sudden onset. Stop med that causes this, else poss Anaphylaxis.
• Common type adverse drug rx
• Intense, vivid color
• Other systemic symptoms possible
• Alert patient to hypersensitivity
(for future prevention)
Urticaria
• Hives
– Pinkish, edematous elevations
– Itch, local discomfort
– Angioneurotic edema = Angio edema (the deeper layers of skin. Includes eyelids, lips,
feet, tongue)
•
Caution for airway obstruction
– Prepare for poss Tracheostomy
Common side effect of ACE Inhibitors
•
Food Allergies
• Type 1 Hypersensitivity
• The Usual Suspects??
– Seafood, legumes, seeds, nuts
– Egg whites, Milk, Chocolate
– Classic allergic and GI symptoms
– N/V/D, swelling of lips and tongue, Abd pain, Wheezing
• Elimination is key to mgmt
• Drug therapy
– H1/H2 blockers
– Antihistamines
– Adrenergic- in case of reaction
– Steroids- reduce inflammation
• Nursing Mgmt – Prevention, Pt & family teaching, recognition of sx
• Latex Allergies
Keep in mind of all the products that contain…
• Implicated as cause in many allergic responses
– Rhinitis
-Conjunctivitis
– Contact dermatitis
-Urticaria “hives”
– Asthma
-Anaphylaxis
Latex Allergy
• 1-3% pop. (10-17% HCW)
• 19% of anesthesia reactions
• Routes of exposure
– Cutaneous, mucosal,
– Parenteral, aerosol (powder)
Latex Allergy
Clinical Manifestations
• Irritant Contact dermatitis (redness, itching)
– Non-immunogenic response
– Erythema, pruritus
– Treatment:
• change brands/type
Latex Allergy - Type 1
• Type I – Immediate
– Rhinitis, conjunctivitis, asthma, anaphylaxis
• Signs & Symptoms:
– Localized itching
-Erythema
– Hives
-Angioedema
– Rhinitis
-Conjunctivitis
– Anaphylactic shock
-Cardiac arrest
Latex Allergy – Type IV
• Type IV – Delayed (Most common type)
– vesicular skin lesions on back of hands, papules, pruritus
– Most common type
• Latex Allergy
Diagnosis:
-Skin tests (Prick Test)
-RAST test (blood sample)
Treatment:
-Avoidance
-Antihistamines
-Emergency supplies
• Ask all patients about allergies before beginning treatment
• Make sure you post signs and remove latex materials from the room.
• Teach pt. epinephrine self-injection