Urticaria (acute)MANAGEMENT

DERMATOLOGY PRESENTATIONS · 12 SECTIONS

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477 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▾

Allergic contact dermatitis Bullous Pemphigoid Cutaneous Abscess Eczema Herpeticum Erysipelas Erythema multiforme Henoch-Schönlein purpura Herpes Zoster (Shingles)Herpetic Whitlow Paronychia Pediculosis (Lice)Pemphigus Vulgaris Pilonidal Abscess Pressure injury Psoriasis (acute flare)Psoriasis Flare Staphylococcal Scalded Skin Syndrome Stevens-Johnson Syndrome (SJS)Toxic Epidermal Necrolysis (TEN)Urticaria (acute)Warfarin-induced Skin Necrosis

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▾

01Approach to the Critical Patient/attcp47

Stabilization priorities

›Immediate threats screen

›Airway compromise signs

›Voice change

›Stridor

›Tongue or floor of mouth swelling

›Breathing compromise signs

›Wheeze

›Hypoxemia

›Circulation compromise signs

›Hypotension

›Syncope

›If anaphylaxis criteria met, initiate epinephrine IM immediately Class I

›Do not delay for antihistamines or steroids

›Repeat epinephrine IM every 5 to 15 minutes if ongoing compromise

›Monitoring and access

›Continuous pulse oximetry for respiratory symptoms

›Frequent reassessment for progression from urticaria to anaphylaxis

›Peak expiratory flow if bronchospasm and cooperative

›IV access if systemic symptoms or angioedema

›Crystalloid bolus if hypotension

›Cardiac monitoring if epinephrine given or significant comorbidity

Key decision points

›Phenotype

›Urticaria without angioedema

›Target symptom control with H1 antihistamine first line Class I

›Discharge common if stable

›Urticaria with angioedema

›Airway risk stratification

›Observation if facial or oral involvement

›Isolated angioedema without hives

›Bradykinin mediated pathway concern

›ACE inhibitor exposure check

›Trigger identification and removal

›Medication exposures

›NSAIDs

›Antibiotics

›Food exposure

›Timing within minutes to 2 hours for IgE mediated pattern

›Physical triggers

›Heat

›Cold

›Escalation triggers

›Progression pattern

›New respiratory symptoms

›New hypotension

›Refractory symptoms

›Persistent angioedema with airway involvement

›Poor response to first line therapy

02History/hx62

Core features

›Symptom timeline and pattern

›Onset time

›Minutes to hours

›Days

›Lesion duration per individual wheal

›Less than 24 hours typical for urticaria

›More than 24 hours with bruising concern for urticarial vasculitis

›Recurrence frequency

›Single episode acute

›Recurrent episodes

›Symptom phenotype

›Pruritus

›Intensity

›Sleep disruption

›Angioedema

›Lips

›Tongue

›Systemic symptoms

›Dyspnea

›Chest tightness

›Exposure history

›New medications within past 1 to 2 weeks

›Antibiotics

›ACE inhibitors

›NSAID exposure

›Aspirin

›Ibuprofen

›Food ingestion within minutes to 2 hours

›Nuts

›Shellfish

›Infection symptoms

›Viral upper respiratory

›Fever

›Prior allergic history

›Prior urticaria episodes

›Similar triggers

›Severity trend

›Anaphylaxis history

›Prior epinephrine use

›Prior intubation

›Atopy

›Asthma

›Allergic rhinitis

Medication and risk modifiers

›Medication list and modifiers

›Beta blocker use

›Reduced response to epinephrine risk

›Glucagon rescue consideration if refractory anaphylaxis

›ACE inhibitor use

›Bradykinin angioedema risk

›Urticaria absence supportive

›Anticoagulants

›Bleeding risk with vasculitis mimics

›Comorbidities

›Asthma

›Higher risk severe anaphylaxis

›Wheeze interpretation

›Cardiovascular disease

›Epinephrine risk benefit framing

›Lower threshold monitoring

›Mast cell disorder history

›Baseline tryptase history

›More severe reactions risk

03Physical Exam/exam51

Skin and mucosa

›Lesion morphology

›Transient wheals

›Blanching

›Raised edematous plaques

›Distribution

›Generalized

›Localized

›Non urticarial flags

›Petechiae

›Purpura

›Angioedema features

›Lip swelling

›Symmetry

›Progression

›Tongue swelling

›Position in mouth

›Speech changes

›Uvula swelling

›Airway narrowing concern

›Drooling

Airway breathing circulation and focused systems

›Airway assessment

›Voice

›Hoarseness

›Muffled voice

›Work of breathing

›Accessory muscle use

›Fatigue

›Oropharyngeal exam

›Posterior pharynx edema

›Tongue base edema

›Respiratory exam

›Wheeze

›Diffuse bronchospasm

›Silent chest concern

›Stridor

›Upper airway obstruction

›Immediate escalation trigger

›Cardiovascular and perfusion

›Blood pressure trend

›Hypotension

›Wide pulse pressure

›Perfusion

›Capillary refill delay

›Cool extremities

›GI and neuro

›Abdominal tenderness

›Severe pain concern for alternative diagnosis

›Persistent vomiting supportive anaphylaxis

›Mental status

›Agitation

›Confusion

04Differential Diagnosis/ddx30

Life threatening and must not miss

›Anaphylaxis ICD 10 T78.2

›Skin plus respiratory or cardiovascular compromise

›Two or more organ systems after likely allergen exposure

›Hereditary angioedema SNOMED CT concept hereditary angioedema

›Recurrent angioedema without hives

›Abdominal pain episodes

›ACE inhibitor angioedema ICD 10 T78.3

›Facial or tongue swelling without pruritic wheals

›On ACE inhibitor exposure

›Urticarial vasculitis ICD 10 L95.8

›Lesions lasting more than 24 hours

›Residual bruising or hyperpigmentation

Mimics and associated conditions

›Contact dermatitis ICD 10 L23

›Vesicles

›Clear contact pattern

›Viral exanthem ICD 10 B09

›Maculopapular lesions

›Associated fever or URI symptoms

›Drug eruption ICD 10 L27

›Morbilliform rash

›Timing days after medication start

›Cellulitis mimic

›Local warmth and tenderness

›Non migratory erythema

›Scabies

›Burrows

›Nocturnal pruritus

›Mastocytosis and mast cell activation

›Recurrent flushing and urticaria

›Hypotension episodes

05Laboratory Tests/lt25

Minimal testing strategy

›Lab approach

›No routine labs for uncomplicated acute urticaria Level B

›Low diagnostic yield in typical cases

›Treatment response not lab dependent

›Targeted labs for alternate diagnosis concern Level C

›Vasculitis suspicion

›Bradykinin angioedema suspicion

Targeted labs when indicated

›Basic tests for systemic involvement

›Complete blood count for infection or hematologic concern

›Eosinophilia supportive drug reaction or parasitic risk

›Leukocytosis supportive infection

›Electrolytes and creatinine for severe vomiting or hypotension

›Dehydration markers

›Acute kidney injury markers

›Anaphylaxis adjuncts

›Serum tryptase for severe reactions and diagnostic uncertainty

›Peak window within 1 to 3 hours after onset

›Normal result does not exclude anaphylaxis

›Bradykinin mediated angioedema evaluation

›C4 level for hereditary angioedema screening

›Low C4 supportive

›Normal C4 does not fully exclude

›C1 esterase inhibitor quantity and function for confirmation

›Low function supportive

›Specialist follow up typical

06Diagnostic Tests/dt35

Scoring Systems

›Criteria frameworks

›NIAID FAAN anaphylaxis criteria

›High sensitivity reported in ED validation studies

›Practical bedside trigger for epinephrine Class I

›WAO anaphylaxis criteria

›Similar to NIAID criteria

›Emphasis on rapid recognition

›Symptom activity tools

›Urticaria Activity Score UAS7 for recurrent patterns

›Daily hive count and itch severity tracking

›Specialist follow up utility

›Angioedema activity or severity tracking tools

›Symptom diary framework

›Trigger correlation aid

MRI

›MRI role

›Not indicated for routine urticaria Level C

›No diagnostic benefit for typical transient wheals

›Avoid delays in time sensitive anaphylaxis care

›Rare indications for alternative diagnosis

›CNS symptoms suggesting other pathology

›Soft tissue evaluation when abscess mimic and CT avoided

›CT role

›Not indicated for isolated urticaria Level C

›Clinical diagnosis

›Low yield

›Indications for airway concern escalation

›Deep neck infection concern

›Severe facial swelling with uncertain source

Ultrasound (or US)

›Ultrasound role

›Not required for typical urticaria Level C

›Lesions superficial and clinical

›Management unchanged

›POCUS adjuncts for unstable presentations

›IVC and cardiac views for shock phenotype

›Lung ultrasound for alternative dyspnea causes

07Disposition/dispo25

Observation and admission criteria

›Disposition stratification

›Discharge criteria

›Isolated urticaria

›No respiratory or cardiovascular symptoms

›Observation criteria

›Angioedema involving lips or face

›Recent epinephrine administration

›Admission criteria

›Airway involvement

›Recurrent symptoms during observation

›Observation timing principles

›Anaphylaxis risk based observation after epinephrine

›Longer observation if severe reaction or multiple epinephrine doses

›Shorter observation may be appropriate if rapid full resolution and low risk

Follow up planning

›Outpatient follow up

›Primary care follow up within 2 to 7 days for persistent symptoms

›Trigger review

›Medication tolerance

›Allergy referral indications

›Suspected food or drug allergy

›Recurrent episodes or angioedema without hives

›Medication safety planning

›Driving and sedation counseling for first generation antihistamines

›Avoid machinery use

›School or work safety discussion

08Treatment/t95

First line symptom control

›H1 antihistamines Class I

›Second generation preferred

›Lower sedation

›Longer duration

›Up dosing to as high as 4 times standard dose for refractory symptoms Level B

›Adult options

›Cetirizine oral

›Standard 10 mg daily

›If refractory, increase to 20 mg daily

›If severe, increase to 40 mg daily in divided doses

›Loratadine oral

›Standard 10 mg daily

›If refractory, increase to 20 mg daily

›If severe, increase to 40 mg daily in divided doses

›Fexofenadine oral

›Standard 180 mg daily

›If refractory, increase to 180 mg twice daily

›If severe, increase to 360 mg twice daily

›Pediatric options

›Cetirizine oral

›Age 2 to 5 years 2.5 to 5 mg daily

›Age 6 years and older 10 mg daily

›Specialist guided up dosing for refractory symptoms

›Loratadine oral

›Age 2 to 5 years 5 mg daily

›Age 6 years and older 10 mg daily

›First generation H1 antihistamines Level C

›Breakthrough nocturnal pruritus use

›Sedation risk

›Anticholinergic effects risk

›Adult options

›Diphenhydramine oral or IV

›25 to 50 mg every 6 hours as needed

›Avoid in high fall risk

›Hydroxyzine oral

›25 mg every 6 to 8 hours as needed

›QT prolongation risk consideration

Adjunct medications

›H2 antihistamines Level C

›Add on for persistent hives despite H1 therapy

›Modest incremental benefit for cutaneous symptoms

›Not a substitute for epinephrine in anaphylaxis

›Adult options

›Famotidine oral or IV

›20 mg twice daily

›Renal dosing adjustment

›Pediatric options

›Famotidine

›0.5 mg per kg per dose twice daily

›Maximum 20 mg per dose

›Systemic corticosteroids Level C

›Indications

›Severe widespread urticaria not controlled with antihistamines

›Significant angioedema without airway compromise

›Risks

›Hyperglycemia

›Mood changes

›Adult options

›Prednisone oral

›40 to 60 mg daily for 3 to 5 days

›No taper needed for short course

›Pediatric options

›Prednisone oral

›1 mg per kg daily for 3 to 5 days

›Maximum 50 mg daily

Anaphylaxis pathway when criteria met

›Epinephrine IM Class I

›Dosing

›0.01 mg per kg of 1 mg per ml solution IM

›Maximum 0.5 mg per dose

›Administration site

›Anterolateral thigh preferred

›Repeat every 5 to 15 minutes if persistent symptoms

›Adjuncts after epinephrine

›Isotonic crystalloid bolus for hypotension

›Inhaled beta agonist for bronchospasm

›Refractory anaphylaxis escalation Class IIa

›Epinephrine infusion for persistent shock after IM dosing

›Initiate in monitored setting

›Titrate to blood pressure and perfusion targets

›Glucagon for beta blocker associated refractory response

›Nausea and vomiting risk

›Continuous monitoring requirement

Trigger avoidance and supportive care

›Avoidance advice Level B

›NSAID avoidance during active episode

›Exacerbation risk

›Alternative analgesics

›Alcohol avoidance during active episode

›Vasodilation worsens pruritus risk

›Sleep disruption risk

›Skin care measures Level C

›Cool compresses

›Itch relief

›Avoid overheating

›Fragrance free emollients

›Barrier support

›Irritant reduction

09Special Populations/sp30

Pregnancy

›Pregnancy considerations

›Maternal stabilization priority Class I

›Epinephrine for anaphylaxis not withheld

›Left lateral positioning for hypotension symptoms

›Antihistamine selection

›Cetirizine acceptable option

›Loratadine acceptable option

›Corticosteroids

›Short course if severe symptoms

›Hyperglycemia monitoring if gestational diabetes

Geriatric

›Older adult considerations

›Sedation vulnerability

›Avoid first generation antihistamines when possible

›Fall risk mitigation

›Anticholinergic burden

›Urinary retention risk

›Delirium risk

›Cardiovascular comorbidity

›Monitoring after epinephrine if anaphylaxis

›Medication interaction review

Pediatrics

›Pediatric considerations

›Anaphylaxis recognition without hypotension

›Respiratory compromise and skin findings common

›Early epinephrine threshold

›Weight based dosing accuracy

›Current weight use

›Maximum dose limits

›Discharge planning

›Caregiver education on recurrence

›Return precautions clearly listed

10Background/b36

Epidemiology

›Epidemiology overview

›Acute urticaria common ED presentation

›Many cases idiopathic

›Infection and medication triggers frequent

›Course

›Most episodes resolve within days to weeks

›Progression to chronic urticaria uncommon

›Anaphylaxis association

›Urticaria may be first visible sign

›Systemic symptoms define severity risk

Pathophysiology

›Mechanisms

›Mast cell activation

›Histamine release drives wheal and flare

›Pruritus mediated by histamine and neuropeptides

›IgE mediated pathway subset

›Rapid onset after exposure

›Higher recurrence with re exposure

›Non IgE mediated pathways

›NSAID related pseudoallergy

›Infection related immune activation

›Bradykinin mediated angioedema

›No urticaria typical

›Poor response to antihistamines and steroids

Therapeutic Considerations

›Treatment rationale

›H1 blockade first line

›Reduces itch and wheal formation

›Second generation preferred for safety

›Up dosing strategy

›Dose response relationship for refractory symptoms

›Monitor sedation and anticholinergic effects

›Steroid role limited

›Short courses for severe refractory symptoms

›Avoid routine use in mild cases

›Epinephrine for anaphylaxis

›Alpha effects improve vascular tone

›Beta effects improve bronchospasm and mediator release

11Patient Discharge Instructions/pdi24

copy discharge instructions

›Discharge instructions

›Diagnosis explanation

›Hives and itching from temporary skin swelling

›Often no single clear trigger found

›Medications

›Daily non drowsy antihistamine as directed

›Avoid extra sedating antihistamines unless advised

›Avoidance

›Avoid NSAIDs during active hives

›Avoid alcohol until symptoms gone

›Skin comfort

›Cool showers

›Cool compresses

›Return to emergency immediately for red flags

›Trouble breathing

›Wheeze

›Throat tightness

›Voice change

›Swelling of tongue or lips that is worsening

›Dizziness or fainting

›Repeated vomiting

›Follow up

›Primary care within 2 to 7 days if not improving

›Allergy referral if repeated episodes or suspected specific trigger

12References/r17

Guidelines and key sources

›Evidence sources

›American Academy of Emergency Medicine guideline on acute urticaria and angioedema

›ED evaluation and management focus

›Limited role for routine laboratory testing

›International urticaria guideline EAACI GA2LEN EuroGuiDerm APAAACI 2021 update

›Second generation H1 antihistamine first line

›Up dosing up to fourfold for refractory symptoms

›Primary care review sources

›Acute urticaria first line second generation H1 antihistamines

›Up dosing strategy cautions

›Anaphylaxis criteria and emergency care sources

›NIAID FAAN anaphylaxis criteria

›High sensitivity in ED validation studies

›Bedside recognition framework

›Pediatric anaphylaxis emergency treatment position statements

›Epinephrine first line

›Antihistamines and steroids second line

Evidence & Review

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

SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.