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Urticaria, Emergency Medicine

Basics

Description

- Edema of the epidermis as well as the upper and middle dermis: - More common in children and young adults - More common in women - More common in the atopic patient

- Foods or additives - Herbal medications, vaccines, opiates - Insect bites and stings - Connective tissue diseases - Endocrine disorders, especially Hashimotos thyroiditis - Cancers, especially lymphoproliferative - Hormonal imbalance, pregnancy, menstrual cycle, exogenous estrogens - Infections: - Viral (including hepatitis, HIV) - Viral URI most common associated infection - Bacterial - Fungal - Parasitic

- Inhaled or contact allergen - Emotional stress - Physical urticaria " ”>20 identified types, including: - Dermographism: - Most common physical form - Reaction to skin pressure - Linear wheals under tight clothing - Areas scratched with a firm object

- Prior history - Familial history - Alleviating and/or aggravating factors - Time course of current presentation: - Often helpful to circle lesions to document their duration - Fever and systemic symptoms - Arthralgias and myalgias - Weight loss and lymphadenopathy - Hypotension, flushing, headache - Swelling of mucosal sites - Respiratory distress or airway symptoms: - May be part of an anaphylactic reaction

- Focus on signs of systemic allergic reaction or infection - Airway " ”angioedema, airway compromise, inability to handle secretions, abnormal phonation, stridor - Breathing " ”wheezing - Circulation " ”systemic signs of anaphylaxis, such as hypotension - Abdomen " ”hepatosplenomegaly, pregnancy - Dermal " ”associated edema, associated petechiae, or purpura: - Generalized, transient, pruritic, well-circumscribed skin eruptions - May include palms or soles - May include bullae or purpuric lesions - Lesions are of various sizes and shapes, haphazard in distribution, and may become confluent - Wheals usually resolve in 3 " “4 hr - New lesions evolve as old ones resolve

- Acute urticaria: No labs needed - Chronic urticaria: - Evaluate for infection or systemic disease: - CBC with differential, ESR, and/or CRP - Thyroid-stimulating hormone and thyroid functions - Urinalysis, liver function tests

- Angioedema: - Can be life-threatening - May have component of abdominal symptoms - Hereditary or acquired

  • Cutaneous mast and basophil cellular release of inflammatory mediators, primarily histamine:Increased vascular permeability and pruritus
  • Edema of the epidermis as well as the upper and middle dermis:More common in children and young adultsMore common in womenMore common in the atopic patient
  • 40% of patients with urticaria will have a component of angioedema:Affects deeper subdermal and/or submucosal sites
  • Urticaria is often the result of reactions to foods and infections
  • Swelling of distal extremities and acrocyanosis may be prominent in infants
  • Bullae may form in the center of the wheal, especially on legs and buttocks

Etiology

Acute: ‚

Presumptive trigger may be found, but majority of cases are idiopathic ‚

Course of <6 wk ‚

  • Drugs:Few have recurrent urticaria on later antigenic challenge
  • Foods or additives
  • Herbal medications, vaccines, opiates
  • Insect bites and stings
  • Connective tissue diseases
  • Endocrine disorders, especially Hashimotos thyroiditis
  • Cancers, especially lymphoproliferative
  • Hormonal imbalance, pregnancy, menstrual cycle, exogenous estrogens
  • Infections:Viral (including hepatitis, HIV)Viral URI most common associated infectionBacterialFungalParasitic
  • Inhaled or contact allergen
  • Emotional stress
  • Physical urticaria " ”>20 identified types, including:Dermographism:Most common physical formReaction to skin pressureLinear wheals under tight clothingAreas scratched with a firm objectCholinergic:Monomorphic wheals 2 " “3 mmBright red flare and intense pruritusA response to elevated core temperature:Other rare forms:Cold-induced (may be fatal in cold immersions)Sun exposureAquagenic

Chronic: ‚

Course of >6 wk ‚

  • 75% idiopathic in nature
  • Autoimmune disease spectrum
  • Immune complex " “induced
  • Often an unrecognized recurring physical urticaria
  • May be due to occult or subclinical infection or systemic disease

Diagnosis

Signs and Symptoms

History

  • Prior history
  • Familial history
  • Alleviating and/or aggravating factors
  • Time course of current presentation:Often helpful to circle lesions to document their durationFever and systemic symptomsArthralgias and myalgiasWeight loss and lymphadenopathyHypotension, flushing, headacheSwelling of mucosal sitesRespiratory distress or airway symptoms:May be part of an anaphylactic reaction

Physical Exam

  • Focus on signs of systemic allergic reaction or infection
  • Airway " ”angioedema, airway compromise, inability to handle secretions, abnormal phonation, stridor
  • Breathing " ”wheezing
  • Circulation " ”systemic signs of anaphylaxis, such as hypotension
  • Abdomen " ”hepatosplenomegaly, pregnancy
  • Dermal " ”associated edema, associated petechiae, or purpura:Generalized, transient, pruritic, well-circumscribed skin eruptionsMay include palms or solesMay include bullae or purpuric lesionsLesions are of various sizes and shapes, haphazard in distribution, and may become confluentWheals usually resolve in 3 " “4 hrNew lesions evolve as old ones resolve
  • Lymphadenopathy
  • Dermographism:Scratch skin with a tongue blade; observe for linear wheal
  • Cholinergic:Exercise challenge to raise core temperature or induce sweating
  • Expose to sunlight
  • Cold-induced:Place an ice cube on skin for 5 min
  • Aquagenic:Apply tap water at differing temperatures
  • Significant mucosal edema:Suspect angioedemaSevere reaction with hypotensionSuspect anaphylaxis
  • Prolonged, painful, or nonblanching lesions:Suspect urticarial vasculitis

Essential Workup

  • Complete history and physical exam
  • Lesion appearance, location, timing, duration
  • Identify as acute vs. chronic time-course
  • Associated symptoms, triggers
  • Coexisting diseases, allergies, medications
  • Evaluate for sources of infection and signs of systemic diseases

Diagnosis Tests & Interpretation

Lab

  • Acute urticaria: No labs needed
  • Chronic urticaria:Evaluate for infection or systemic disease:CBC with differential, ESR, and/or CRPThyroid-stimulating hormone and thyroid functionsUrinalysis, liver function tests
  • Skin biopsy if urticarial vasculitis suspected (not done in ED)

Imaging

  • Acute cases: Not needed
  • Chronic cases:Directed at search for occult infection

Diagnostic Procedures/Surgery

Skin biopsy " ”for chronic urticaria or urticarial vasculitis ‚

Differential Diagnosis

  • Angioedema:Can be life-threateningMay have component of abdominal symptomsHereditary or acquired
  • Cutaneous vasculitis
  • Serum sickness
  • Erythema multiforme
  • Bullous pemphigoid
  • Juvenile rheumatoid arthritis
  • Erythema marginatum
  • Dermatitis herpetiformis
  • Systemic mastocytosis
  • Henoch " “Schonlein purpura

Treatment

Pre-Hospital

  • Cautions:Systemic allergic reactions can rapidly progress if not treated with early epinephrine
  • Severe reaction:Manage airway, oxygenIM epinephrineParenteral or inhaled Ž ²-agonist for bronchospasmIV crystalloid and vasopressors as needed

Initial Stabilization/Therapy

Remove offending agent if possible ‚

Ed Treatment/Procedures

  • Largely symptomatic except in severe reactions
  • Treatment aimed at stimulus, effector cells, inflammatory mediators, and target receptors
  • Ž ²-Agonist (parenteral or inhaled):Severe hives, angioedema, systemic features
  • H1-receptor antagonist (1st or 2nd generation):
  • H2-receptor antagonist:May be beneficial as adjunct to H1 blocker when no response to H1 blocker alone
  • Corticosteroid (oral):Severe or refractory cases
  • Avoid NSAIDs and opiates:
  • Concurrent use of ketoconazole or macrolides alters hepatic metabolism of antihistamine; use with caution

Medication

  • Ž ²-Agonists:Epinephrine (1:1,000 solution): 0.1 " “0.5 mg IM q10 " “15min PRN (peds: 0.01 mg/kg, IM [max. single dose not to exceed 0.3 mg] q15min PRN)IV epinephrine 0.1 " “0.25 mg (1:10,000 sol) IV over 5 " “10 min q5 " “15min then 1 " “4 Ž ¼g/min IV ONLY if anaphylactic shockAlbuterol (0.5% solution): 0.5 mL nebulized q20min PRN (peds: 0.01 " “0.05 mL/kg per dose [max. 0.5 mL/dose] nebulized q20min PRN bronchospasm)Terbutaline: 0.25 mg SC q15 " “30min PRN (max. 0.5 mg q4h); (peds: <12 yr old; 0.005 " “0.01 mg/kg [max. 0.4 mg/dose] SC q15 " “20min ƒ — 3 PRN bronchospasm)
  • H1-receptor antagonist (1st generation " ”lipophilic and sedating)Diphenhydramine: 25 " “50 mg PO, IV, or IM q6h (peds: 1 mg/kg q6h [max. 300 mg/24 h])Hydroxyzine: 25 " “50 mg PO or IM q6h (peds: 2 mg/kg/24 h PO div. q8h or 0.5 " “1 mg/kg IM q4 " “6h PRN)
  • H1-receptor antagonist (2nd generation " ”less sedating and preferred):Cetirizine: Adult and peds ≥6 yr old: 5 " “10 mg PO QD (peds 2 " “6 yr old: 2.5 mg QD to BID)Loratadine: 10 mg PO BID (peds 2 " “6 yr old: 5 mg PO QDFexofenadine: 60 mg PO BID or 180 mg PO QD (peds 6 " “12 yr old: 30 mg PO BID)
  • H2-receptor antagonist (suggested dosage):Famotidine: 20 mg IV q12h or 20 " “40 mg PO QHS (peds: 1 mg/kg/d div. QID [max. 40 mg/24 h])Ranitidine: 150 mg PO BID (peds: Neonate: 2 " “4 mg/kg/24 h PO div. q8 " “12h or 2 mg/kg/24 h IV div. q6 " “8h; infants and children: 4 " “5 mg/kg/24 h PO div. q8 " “12h or 2 " “4 mg/kg/24 h IV or IM div. q6 " “8h)
  • Corticosteroid:Methylprednisolone: 125 mg IV (peds: Start at 2 mg/kg ƒ — 1)Prednisolone: 50 mg PO QD for 3 days (peds: 0.5 " “2 mg/kg/24 h [max. 80 mg/24 h] div. QD to BID for 3 " “5 days)Prednisone: 40 mg PO QD or 20 mg PO BID for 3 " “5 days (peds: 1 " “2 mg/kg/24 h [max. 80 mg/24 h] div. QD to BID for 3 " “5 days)
  • Antileukotrienes:Montelukast: 10 mg PO QDZafirlukast: 20 mg PO BID

First Line

  • H1-receptor antagonist, 2nd generation
  • Corticosteroids
  • Ž ²-Agonists:Albuterol if bronchospasm presentEpinephrine for severe or systemic signs

Second Line

  • Antileukotrienes
  • H1-receptor antagonist, 1st generation
  • H2-receptor antagonist, data weak

Follow-Up

Disposition

Admission Criteria

  • Systemic allergic reaction with:Respiratory distress or failureRefractory hypotension or shock
  • Severe case with dysfunction of health-related quality of life
  • Other comorbidities

Discharge Criteria

  • Normal vitals
  • Absence of other condition requiring admission
  • Adequate ability of caregivers at home to monitor for further exacerbations

Followup Recommendations

Follow with PCP, especially if lasting >6 wk ‚

Pearls and Pitfalls

  • If severe presentation, there is often a biphasic course. Rebound may occur in 4 " “6 hr
  • Chronic urticaria often has a systemic cause

Additional Reading

  • Kropfl ‚ L, Mauer ‚ M, Zuberbier ‚ T. Treatment strategies in urticaria. Expert Opin. Pharmacother. 2010;11:1445 " “1450.
  • Nichols ‚ K, Cook-Bolden ‚ F. Allergic skin disease: Major highlights and recent advances. Med Clin N Am. 2009;93:1211 " “1224.
  • Ricci ‚ G, Giannetti ‚ A, Belotti ‚ T, et al. Allergy is not the main trigger of urticaria in children referred to the emergency room. J Eur Acad Dermatol Venereol. 2010;24:1347 " “1348.
  • Wolfson ‚ AB, Hendey ‚ GW, Ling ‚ LJ, et al. (eds) Harwood-Nuss ' Clinical Practice of Emergency Medicine. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2010.
  • Zuberbier ‚ T. A summary of the new international EAACI/GA(2)LEN/EDF/WAO guidelines in urticaria. WAO J. 2012;5(suppl 1):S1 " “S5.
  • Zuberbier ‚ T, Asero ‚ R, Bindslev-Jensen ‚ C, et. al. EAACI/GA2LEN/EDF/WAO guideline: definition, classification, and diagnosis of urticaria. Allergy. 2009;64:1417 " “1426.

See Also (Topic, Algorithm, Electronic Media Element)

  • Angioedema
  • Erythema Multiforme
  • Vasculitis

Codes

ICD9

  • 708.0 Allergic urticaria
  • 708.1 Idiopathic urticaria
  • 708.9 Unspecified urticaria
  • 708.8 Other specified urticaria
  • 995.1 Angioneurotic edema, not elsewhere classified

ICD10

  • L50.0 Allergic urticaria
  • L50.1 Idiopathic urticaria
  • L50.9 Urticaria, unspecified
  • L50.6 Contact urticaria
  • T78.3XXA Angioneurotic edema, initial encounter

SNOMED

  • 126485001 urticaria (disorder)
  • 40178009 Allergic urticaria (disorder)
  • 42265009 Idiopathic urticaria (disorder)
  • 19364004 contact urticaria (disorder)
  • 41291007 angioedema (disorder)