AngioedemaMANAGEMENT

SYSTEMIC AND MISCELLANEOUS PRESENTATIONS · 12 SECTIONS

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472 items

☷ Legend

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Cardiovascular Presentations66▾

Respiratory Presentations47▾

Neurological Presentations77▾

Gastrointestinal Presentations63▾

Genitourinary and Reproductive Presentations44▾

Infectious Disease Presentations146▾

Trauma Presentations88▾

Toxicologic Presentations67▾

Psychiatric Presentations25▾

Musculoskeletal and Rheumatologic Presentations89▾

Dermatology Presentations21▾

Environmental and Exposure Presentations26▾

Hematologic and Oncologic Presentations30▾

Pediatric-Specific Presentations13▾

Endocrine and Metabolic Presentations42▾

ENT and Maxillofacial Presentations21▾

Ophthalmologic Presentations15▾

Obstetric Presentations17▾

Systemic and Miscellaneous Presentations15▾

Allergic Transfusion Reaction Anaphylaxis Angioedema Benedikt's Syndrome Cannabis-induced hyperemesis Eczema (acute flare)Gradenigo's Syndrome Horner's Syndrome (Acute)Huntington's Disease (Acute Presentation)Kanavel's Signs Lemierre's Syndrome Radiation exposure Retained products of conception Sever's Disease Urticaria

01Approach to the Critical Patient/attcp49

Airway first

›Airway risk stratification

›Voice change

›Hoarseness

›Muffled voice

›Stridor

›Inspiratory

›Biphasic

›Drooling

›Inability to handle secretions

›Tripod posture

›Tongue and floor-of-mouth swelling

›Rapid progression minutes to hours

›Inability to protrude tongue

›Laryngeal involvement

›Sensation of throat tightness

›Globus with respiratory symptoms

›High risk anatomy involvement

›Posterior tongue

›Soft palate

Immediate actions and monitoring

›Time critical stabilization

›Escalate to resuscitation bay for any airway symptoms

›Early anesthesia and ENT involvement

›Difficult airway cart at bedside

›Continuous monitoring

›Pulse oximetry

›Cardiac monitoring

›IV access

›2 large bore peripheral lines if severe

›Oxygen support

›Nasal cannula to nonrebreather by work of breathing

›High flow nasal cannula if impending fatigue

Angioedema phenotype triage

›Mechanism classification

›Histamine mediated

›Urticaria

›Pruritus

›Bronchospasm

›Hypotension

›Bradykinin mediated

›No urticaria

›Slower onset hours

›Prominent facial, lip, tongue swelling

›Abdominal pain episodes

Early airway intervention triggers

›Airway intervention decision points

›If stridor or progressive voice change, early awake approach

›Awake fiberoptic intubation favored when feasible

›Ketamine preferred if sedation needed and airway reflexes preserved

›If inability to handle secretions, airway control before deterioration

›Prepare for surgical airway backup

›Cricothyrotomy kit opened at bedside

02History/hx61

Key history elements

›Symptom timeline

›Onset time

›Minutes suggests histamine mediated

›Hours suggests bradykinin mediated

›Progression rate

›Rapid expansion

›Plateau then resolution

›Prior episodes

›Similar swelling

›Abdominal attacks

›Exposure and triggers

›Food exposure

›New food

›Known allergen

›Medication triggers

›ACE inhibitor use

›ARB use

›NSAID exposure

›Aspirin

›Ibuprofen

›Sting exposure

›Hymenoptera

›Other arthropods

›Associated symptoms

›Urticaria

›Diffuse wheals

›Dermatographism

›Respiratory symptoms

›Dyspnea

›Wheeze

›Cardiovascular symptoms

›Syncope

›Dizziness

›GI symptoms

›Crampy abdominal pain

›Vomiting

›Risk factors for hereditary or acquired C1 inhibitor deficiency

›Family history

›Recurrent swelling

›Unexplained abdominal pain

›Estrogen exposure

›OCP use

›Pregnancy

›Lymphoproliferative disease history

›CLL

›Non-Hodgkin lymphoma

Medication and allergy review

›Current medications

›ACE inhibitor name and start date

›First month risk

›Late onset possible

›DPP-4 inhibitor use

›Sitagliptin class association

›Neprilysin inhibitor combination use

›Sacubitril related risk

›Allergy history

›Prior anaphylaxis

›Trigger identified

›Epinephrine auto-injector availability

›Prior reactions to contrast

›Immediate hypersensitivity features

›Need for alternative imaging

03Physical Exam/exam44

Airway and respiratory findings

›Upper airway findings

›Lip swelling

›Asymmetry

›Tension and progression

›Tongue enlargement

›Anterior tongue

›Posterior tongue

›Floor-of-mouth edema

›Sublingual space fullness

›Saliva pooling

›Oropharynx

›Uvula edema

›Soft palate swelling

›Respiratory status

›Work of breathing

›Accessory muscle use

›Fatigue

›Auscultation

›Wheeze

›Silent chest

›Stridor assessment

›At rest

›With speech

Skin and systemic exam

›Skin findings

›Urticaria distribution

›Generalized

›Localized

›Flushing

›Histamine mediated clue

›Anaphylaxis clue

›Hemodynamics

›Blood pressure trends

›Hypotension suggests anaphylaxis

›Hypertension not reassuring

›Perfusion

›Cool extremities

›Delayed capillary refill

PITFALLS

›Common pitfalls

›Normal oxygen saturation despite critical upper airway obstruction

›Reliance on pulse oximetry alone

›Delay in airway escalation

›Absence of urticaria does not exclude severe angioedema

›Bradykinin mediated phenotypes

›ACE inhibitor associated disease

04Differential Diagnosis/ddx41

Primary and life threats

›Angioedema syndromes

›Histamine mediated angioedema (ICD-10 T78.3XXA)

›Allergic angioedema

›Idiopathic histaminergic

›ACE inhibitor associated angioedema (ICD-10 T78.3XXA)

›Bradykinin mediated

›Refractory to antihistamines and steroids

›Hereditary angioedema (ICD-10 D84.1)

›C1 inhibitor deficiency

›Normal C1 inhibitor with factor XII variants

›Acquired C1 inhibitor deficiency

›Lymphoproliferative association

›Autoantibody association

›Anaphylaxis (ICD-10 T78.2XXA)

›Airway swelling plus hypotension

›Rapid onset

›Multisystem involvement

›Isolated hypotension after exposure

›Occult airway risk

›Need for epinephrine

Mimics and alternative diagnoses

›Infectious and inflammatory

›Ludwig angina

›Fever

›Dental source

›Peritonsillar abscess

›Trismus

›Uvular deviation

›Epiglottitis

›Severe odynophagia

›Drooling

›Trauma and mechanical

›Airway foreign body

›Sudden choking

›Focal wheeze

›Hematoma of tongue or floor-of-mouth

›Anticoagulation use

›Trauma history

›Allergic and dermatologic

›Acute urticaria without angioedema

›No mucosal involvement

›Normal airway

05Laboratory Tests/lt30

Acute severity and anaphylaxis evaluation

›Initial labs for severe presentations

›Point-of-care glucose for altered mental status

›Hypoglycemia mimic of shock

›Rapid correction pathway

›Venous blood gas for respiratory fatigue concern

›Rising CO2 trend

›Worsening acidosis

›Serum lactate for shock physiology

›Elevated supports hypoperfusion

›Trend for response to therapy

Mechanism directed testing

›Complement and bradykinin pathway labs

›C4 level for suspected hereditary or acquired angioedema

›Low during attacks supports C1 inhibitor deficiency

›Normal does not fully exclude

›C1 inhibitor antigen level

›Low in type I HAE

›Normal in type II HAE

›C1 inhibitor functional assay

›Low function in type II HAE

›Needed for confirmation

›C1q level for suspected acquired angioedema

›Low suggests acquired C1 inhibitor deficiency

›Normal more consistent with hereditary

Allergy and mast cell evaluation

›Mast cell activation markers

›Serum tryptase for suspected anaphylaxis

›Peak within hours

›Supports mast cell mediated reaction

›Eosinophil count in selected cases

›Not diagnostic

›Baseline allergy context

06Diagnostic Tests/dt45

Scoring Systems

›Airway involvement staging

›Ishoo staging framework

›Stage 1

›Isolated lip and face

›Low airway intervention rate

›Stage 2

›Soft palate involvement

›Moderate observation need

›Stage 3

›Tongue involvement

›Higher airway intervention risk

›Stage 4

›Laryngeal involvement

›Highest airway intervention risk

›Clinical application

›Stage 3 to 4, ICU level monitoring consideration

›Stage 1 to 2, ED observation if stable and improving

MRI

›MRI role

›Limited acute utility

›Time and airway risk constraints

›Not first line for airway assessment

›Selected indications

›Deep neck space concern when CT contraindicated

›Recurrent atypical swelling evaluation outpatient

›CT neck with contrast

›Indications

›Suspected deep neck infection mimic

›Unclear anatomy and progression

›Limitations

›Does not replace laryngoscopy for laryngeal edema

›Transport risk in unstable airway

›Allergy considerations

›Prior contrast reaction not equivalent to bradykinin angioedema

›Shared decision on risk mitigation

Ultrasound (or US)

›Point-of-care applications

›Upper airway US as adjunct

›Tongue thickness trends

›Submandibular edema assessment

›Lung US for wheeze and respiratory failure differential

›B lines and edema assessment

›Pneumothorax exclusion when dyspnea unclear

›Direct visualization tests

›Flexible nasolaryngoscopy

›Laryngeal edema assessment

›Disposition guidance based on progression

07Disposition/dispo34

Level of care and observation

›ICU criteria

›Any laryngeal involvement on laryngoscopy

›Need for frequent reassessment

›Airway intervention readiness

›Recurrent or progressive tongue or floor-of-mouth swelling

›Failure to improve after initial therapy

›Rapid progression pattern

›Anaphylaxis with hypotension or respiratory compromise

›Epinephrine infusion need

›Biphasic reaction risk

›Observation unit criteria

›Stable stage 1 to 2 anatomy with improvement

›No voice change

›No dyspnea at rest

›ACE inhibitor angioedema without airway symptoms but significant facial involvement

›Serial exams

›Escalation triggers predefined

›Discharge criteria

›Complete symptom stability or clear improvement trend

›No progression over observation window

›Normal speech and swallowing

›Reliable follow-up and return precautions

›Medication access

›Transportation and support

Consultation and transfer

›Specialty involvement

›ENT for airway anatomy involvement

›Laryngoscopy findings

›Surgical airway contingency

›Allergy and immunology for recurrent or suspected hereditary disease

›Outpatient workup plan

›Long term prophylaxis discussion

›Transfer triggers

›Need for advanced airway team

›Need for C1 inhibitor products not available

08Treatment/t73

Anaphylaxis and histamine mediated pathway

›Epinephrine for anaphylaxis features (Class I)

›Epinephrine IM 0.5 mg

›Adult dose 0.5 mg of 1 mg/mL solution

›Anterolateral thigh preferred

›Epinephrine IM 0.01 mg/kg

›Pediatric maximum 0.3 mg

›Repeat every 5 to 15 minutes if needed

›If refractory hypotension, initiate epinephrine infusion

›1 to 10 mcg/min titration to perfusion

›Continuous monitoring and frequent reassessment

›Antihistamines as adjunct (Class IIa)

›Diphenhydramine IV 25 to 50 mg

›Sedation risk

›Not airway definitive therapy

›Cetirizine PO 10 mg

›Less sedation option

›For mild cases and discharge planning

›Famotidine IV 20 mg

›Adjunct for urticaria

›Limited impact on airway

›Corticosteroids as adjunct (Class IIb)

›Methylprednisolone IV 125 mg

›Delayed onset hours

›Not a substitute for epinephrine

›Prednisone PO 40 to 60 mg daily

›Short course 3 to 5 days for urticaria predominant

›Hyperglycemia risk

›Bronchospasm treatment if present

›Salbutamol nebulized 5 mg

›Repeat based on response

›Consider continuous nebs if severe

›Ipratropium nebulized 0.5 mg

›Adjunct in severe bronchospasm

›Combine with salbutamol

Bradykinin mediated pathway

›ACE inhibitor associated angioedema

›Immediate ACE inhibitor discontinuation

›Avoid re-challenge permanently

›Document as medication reaction

›Targeted therapies when available

›Icatibant 30 mg SC

›Repeat every 6 hours if needed

›Maximum 3 doses in 24 hours

›C1 inhibitor concentrate

›20 units/kg IV for plasma derived products

›Monitor for thrombotic risk in high risk patients

›Fresh frozen plasma 2 units IV

›Consider when targeted agents unavailable

›Volume overload risk

›Hereditary angioedema acute attack

›C1 inhibitor concentrate 20 units/kg IV

›Early administration improves symptom control

›Repeat dosing per product guidance if incomplete response

›Ecallantide 30 mg SC where available

›Anaphylaxis risk

›Observation after administration

›Icatibant 30 mg SC

›Patient self-administration possible if prescribed

›ED use for severe attacks

Airway management strategy

›Airway escalation

›If progressive tongue, floor-of-mouth, or laryngeal edema, proceed to early definitive airway

›Awake fiberoptic approach preferred when feasible

›Surgical airway backup prepared

›If intubation fails and cannot ventilate, immediate cricothyrotomy

›Time critical action

›Team role assignment before attempt

Supportive care

›Fluids for hypotension

›Crystalloid bolus 20 mL/kg

›Reassess perfusion after each bolus

›Consider early vasopressors if ongoing shock

›Antiemetics for severe nausea

›Ondansetron IV 4 mg

›QT prolongation consideration

›Repeat dosing as needed

09Special Populations/sp30

Pregnancy

›Pregnancy considerations

›Epinephrine for anaphylaxis remains first line (Class I)

›Maternal resuscitation priority

›Left uterine displacement if hypotensive

›Medication safety

›Cetirizine preferred over sedating antihistamines when feasible

›Steroids acceptable when clinically indicated

›Bradykinin mediated disease

›Hereditary angioedema attacks can increase during pregnancy

›C1 inhibitor concentrate preferred acute therapy

Geriatric

›Older adult considerations

›ACE inhibitor exposure prevalence

›High index of suspicion without urticaria

›Polypharmacy review

›Epinephrine caution without delay

›Monitor for ischemia and dysrhythmia

›Benefit outweighs risk in anaphylaxis

›Volume sensitivity

›FFP volume overload risk

›Adjust fluid boluses to comorbidities

Pediatrics

›Pediatric considerations

›Weight based epinephrine IM 0.01 mg/kg (Class I)

›Maximum 0.3 mg per dose

›Repeat every 5 to 15 minutes if needed

›Airway anatomy risk

›Smaller diameter airway

›Earlier deterioration possibility

›Hereditary angioedema suspicion

›Recurrent swelling without urticaria

›Family history triggers evaluation

10Background/b30

Epidemiology

›Epidemiology overview

›Angioedema clinical burden

›Common ED presentation

›Significant airway risk subset

›ACE inhibitor associated angioedema

›Can occur anytime during therapy

›Discontinuation prevents recurrence risk

›Hereditary angioedema

›Rare disorder

›Recurrent attacks over lifetime

Pathophysiology

›Mechanisms

›Histamine mediated vascular permeability

›Mast cell activation

›Often with urticaria

›Bradykinin mediated vascular permeability

›ACE inhibitor impaired bradykinin degradation

›C1 inhibitor deficiency increased kallikrein activity

›Clinical implications

›Histamine pathway responds to epinephrine and antihistamines

›Bradykinin pathway often refractory to antihistamines and steroids

Therapeutic Considerations

›Treatment principles

›Airway protection as primary determinant of outcome

›Early recognition of progression

›Early specialist involvement

›Epinephrine for anaphylaxis is time critical (Class I)

›Reduces mortality risk

›Antihistamines are adjunct only

›Bradykinin targeted agents

›Icatibant as bradykinin B2 receptor antagonist

›C1 inhibitor concentrate replaces deficient inhibitor

11Patient Discharge Instructions/pdi22

copy discharge instructions

›Discharge instructions

›Diagnosis explanation

›Swelling episode consistent with angioedema

›Possible triggers reviewed

›Medication plan

›If allergic features, antihistamine daily for several days

›If steroid prescribed, complete short course as directed

›Avoidance plan

›Avoid ACE inhibitors permanently if suspected cause

›Avoid known triggers and NSAIDs if prior reactions

›Epinephrine auto-injector plan when indicated

›Carry at all times if anaphylaxis risk

›Use immediately for trouble breathing, throat tightness, fainting, or widespread hives

›Return to ED now for red flags

›Voice change or hoarseness

›Trouble breathing or wheeze

›Trouble swallowing or drooling

›Tongue swelling or worsening facial swelling

›Dizziness, fainting, or low blood pressure symptoms

›Follow-up

›Primary care within 1 to 3 days

›Allergy and immunology referral for recurrent episodes or suspected hereditary disease

12References/r13

Guidelines and evidence

›Guideline sources

›ACEP clinical policy and evidence levels for anaphylaxis and allergic emergencies

›Epinephrine as first line for anaphylaxis (ACEP Level B to C depending on endpoint and setting)

›Antihistamines and steroids as adjuncts only (ACEP Level C)

›World Allergy Organization anaphylaxis guidance

›IM epinephrine first line

›Observation for biphasic reaction based on severity

›AAAAI and ACAAI practice parameters for anaphylaxis and angioedema

›Differentiation of histamine vs bradykinin mediated disease

›Role of C4 and C1 inhibitor testing for hereditary disease

›HAE international consensus guidance

›C1 inhibitor concentrate and icatibant for acute attacks

›Avoidance of ACE inhibitors in hereditary disease

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Reviewed by SymptomDx Medical Team · Last reviewed June 16, 2026

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