Allergic Reactions & Allergic Reactions & AnaphylaxisAnaphylaxis
IncidenceIncidence In USA - 400 to 800 deaths/yearIn USA - 400 to 800 deaths/year Parenterally administered penicillin Parenterally administered penicillin
accounts for 100 to 500 deaths per accounts for 100 to 500 deaths per yearyear
Hymenoptera stings account for 40 Hymenoptera stings account for 40 to 100 deaths per yearto 100 deaths per year
Risk factors: beta-blockers, adrenal Risk factors: beta-blockers, adrenal insufficiencyinsufficiency
Causes of DeathsCauses of Deaths Laryngeal edema and acute Laryngeal edema and acute
bronchospasm with respiratory bronchospasm with respiratory failure account for >70%failure account for >70%
Circulatory collapse accounts for Circulatory collapse accounts for 25%25%
Other <5% - ?brain ?MIOther <5% - ?brain ?MI
Allergic ReactionAllergic Reaction
Physiologic response to antigensPhysiologic response to antigens• Oversensitive response = allergicOversensitive response = allergic• Occurs after sensitization to Occurs after sensitization to
antigenantigen Antigen binds with AntibodyAntigen binds with Antibody
• Less severe reaction from the Less severe reaction from the inflammatory response inflammatory response
Allergic ReactionsAllergic Reactions
Generally classified into 3 groups:Generally classified into 3 groups:• Mild allergic reactionMild allergic reaction• Moderate allergic reactionModerate allergic reaction• Severe allergic reaction Severe allergic reaction
(anaphylaxis)(anaphylaxis)
Mild Allergic ReactionMild Allergic Reaction CharacteristicsCharacteristics
• Urticaria (hives), itchyUrticaria (hives), itchy• Erythema (redness)Erythema (redness)• RhinitisRhinitis• ConjunctivitisConjunctivitis• Mild bronchoconstrictionMild bronchoconstriction• Usually localized (look on abdomen, Usually localized (look on abdomen,
chest, back)chest, back) No SOB or hypotension/hypoperfusionNo SOB or hypotension/hypoperfusion Often self-treated at homeOften self-treated at home
UrticariaUrticaria
Moderate Allergic ReactionModerate Allergic Reaction
CharacteristicsCharacteristics• Mild signs/symptoms Mild signs/symptoms withwith any of any of
following:following: Dyspnea, possibly with wheezesDyspnea, possibly with wheezes Angioneurotic edemaAngioneurotic edema Systemic, not localizedSystemic, not localized
No hypotension/hypoperfusionNo hypotension/hypoperfusion
Angioneurotic EdemaAngioneurotic Edema
Severe Allergic Reaction Severe Allergic Reaction (Anaphylaxis)(Anaphylaxis)
CharacteristicsCharacteristics• Mild and/or moderate Mild and/or moderate
signs/symptoms plussigns/symptoms plus• Shock / hypoperfusionShock / hypoperfusion• Respiratory distressRespiratory distress
AnaphylaxisAnaphylaxis
Manifestation of immediate Manifestation of immediate hypersensitivity in which the hypersensitivity in which the
exposure of a sensitized individual to exposure of a sensitized individual to a specific antigen results in life-a specific antigen results in life-threatening respiratory distress threatening respiratory distress
followed by vascular collapse and followed by vascular collapse and shock.shock.
PathophysiologyPathophysiology
AntigenAntigen• Induces antibody formationInduces antibody formation• ExamplesExamples
Drugs (antibiotics)Drugs (antibiotics) Foods (nuts, shellfish)Foods (nuts, shellfish) Insect venomsInsect venoms Animal serumAnimal serum Incompatible blood typesIncompatible blood types
PathophysiologyPathophysiology
Antigen enters bodyAntigen enters body• Ingestion, absorption, inhalation, Ingestion, absorption, inhalation,
injectioninjection Antibodies producedAntibodies produced Attach to surface of mast or basophil Attach to surface of mast or basophil
cellscells Mast cells become sensitizedMast cells become sensitized
PathophysiologyPathophysiology Mast cellsMast cells
• In all subcutaneous/submucosal In all subcutaneous/submucosal tissues, tissues,
• Including conjunctiva, upper/lower Including conjunctiva, upper/lower respiratory tracts, and gutrespiratory tracts, and gut
BasophilsBasophils• Circulate in bloodCirculate in blood
PathophysiologyPathophysiology
Antigen reenters bodyAntigen reenters body Attaches to antibodies on mast or basophil Attaches to antibodies on mast or basophil
cellscells Mast cell degranulates, releasesMast cell degranulates, releases
• HistamineHistamine• LeukotrienesLeukotrienes• Slow reacting substance of anaphylaxis Slow reacting substance of anaphylaxis
(SRS-A)(SRS-A)• Eosinophil chemotactic factor (ECF)Eosinophil chemotactic factor (ECF)
VasodilationVasodilation
Decreased peripheral vascular Decreased peripheral vascular resistanceresistance
HypotensionHypotension TachycardiaTachycardia Peripheral hypoperfusionPeripheral hypoperfusion
Increased Capillary PermeabilityIncreased Capillary Permeability
Tissue edema, urticaria (hives), Tissue edema, urticaria (hives), itchingitching
Laryngeal edemaLaryngeal edema• Airway obstructionAirway obstruction• Respiratory distressRespiratory distress• StridorStridor
Fluid leakage from vascular spaceFluid leakage from vascular space• Hypovolemic shockHypovolemic shock
Smooth Muscle SpasmSmooth Muscle Spasm
BronchospasmBronchospasm• Respiratory Respiratory
distressdistress• ““Tight Chest” Tight Chest” • WheezingWheezing
GI Tract SpasmGI Tract Spasm• Nausea, vomitingNausea, vomiting• Cramping, Cramping,
diarrheadiarrhea
Bladder SpasmBladder Spasm• Urinary urgencyUrinary urgency• Urinary Urinary
incontinenceincontinence
PresentationPresentation
Dependent on:Dependent on:• Degree of hypersensitivityDegree of hypersensitivity• Quantity, route, rate of antigen Quantity, route, rate of antigen
exposureexposure• Pattern of mediator releasePattern of mediator release• Target organ sensitivity and Target organ sensitivity and
responsivenessresponsiveness
PresentationPresentation
Severity varies from mild to fatalSeverity varies from mild to fatal Most reactions are respiratory, Most reactions are respiratory,
dermatologicdermatologic Less severe early findings may progress Less severe early findings may progress
to life-threatening over a short timeto life-threatening over a short time Initial signs/symptoms do Initial signs/symptoms do NOTNOT necessarily necessarily
correlate with severity, progression, correlate with severity, progression, duration of responseduration of response
Generally, quicker symptoms = more Generally, quicker symptoms = more severe reactionssevere reactions
PresentationPresentation First manifestations involve skinFirst manifestations involve skin
• Warmth and tingling of the face, Warmth and tingling of the face, mouth, upper chest, palms and/or mouth, upper chest, palms and/or soles, or site of exposuresoles, or site of exposure
• ErythemaErythema• Pruritus is Pruritus is universaluniversal feature, feature,
erythemaerythema• May be accompanied by generalized May be accompanied by generalized
flushing, urticaria, nonpruritic flushing, urticaria, nonpruritic angioedemaangioedema
PresentationPresentation May progress to involvement of May progress to involvement of
respiratory systemrespiratory system• coughcough• chest tightnesschest tightness• dyspneadyspnea• wheezingwheezing• throat tightnessthroat tightness• dysphagiadysphagia• hoarsenesshoarseness
PresentationPresentation Other Signs and SymptomsOther Signs and Symptoms
• lightheadedness or syncope caused lightheadedness or syncope caused by hypotension or dysrhythmiaby hypotension or dysrhythmia
• nasal congestion and sneezingnasal congestion and sneezing• ocular itching and tearingocular itching and tearing• cramping abdominal pain with cramping abdominal pain with
nausea,vomiting, or diarrheanausea,vomiting, or diarrhea• bowel or bladder incontinencebowel or bladder incontinence• decreased level of consciousnessdecreased level of consciousness
Physical ExamPhysical Exam Findings may include:Findings may include:
• urticaria, angioedema, rhinitis, urticaria, angioedema, rhinitis, conjunctivitisconjunctivitis
• tachypnea, tachycardia, tachypnea, tachycardia, hypotensionhypotension
• laryngeal stridor, hypersalivation, laryngeal stridor, hypersalivation, hoarseness, angioedemahoarseness, angioedema
Patient CarePatient Care
ABCsABCs
MedicsMedics
EpiPen for anaphylaxsisEpiPen for anaphylaxsis
Position of comfortPosition of comfort
OxygenOxygen
Calm & reassure the patientCalm & reassure the patient
TransportTransport
ALS IndicatorsALS Indicators
Unstable vital signsUnstable vital signs EpiPen useEpiPen use Respiratory DistressRespiratory Distress Signs & symptoms of shock:Signs & symptoms of shock:
• Poor skin signsPoor skin signs• Sustained tachycardiaSustained tachycardia• HypotensionHypotension
Top Related