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eMedicine Specialties > Pediatrics: General Medicine > Infectious Disease

Croup

Antonio Muñiz, MD, Associate Professor of Emergency Medicine and Pediatrics, University of Texas Medical School at Houston; Medical Director of the Pediatric Emergency Department, Children's Memorial Hermann Hospital
Rona E Molodow, MD, JD, Clinical Professor, Department of Pediatrics, Olive View-University of California Los Angeles Medical Center; Germaine L Defendi, MD, MS, FAAP, Associate Clinical Professor, Department of Pediatrics, Olive View-UCLA Medical Center

Updated: Nov 18, 2009

Introduction

Background

Croup, also termed laryngotracheitis or laryngotracheobronchitis, is a viral respiratory tract infection. It is primarily a pediatric illness and, as its alternative names indicate, generally affects the larynx and trachea but may also extend to the bronchi. It is the most common etiology for stridor in febrile children. It is a common pediatric illness, with the vast majority of children recovering with no consequences; however, it may be life-threatening. Croup manifests as hoarseness, a seal-like barking cough and a variable degree of respiratory distress. However, morbidity is secondary to narrowing of the larynx and trachea below the level of the glottis, causing the hallmark inspiratory stridor.

Stridor is a relatively common complaint; however, it can alarm parents enough to prompt an emergency department (ED) visit. Stridor is an audible harsh, high-pitched musical sound produced by turbulent airflow through a partially obstructed upper airway. During inspiration, areas of the airway that are easily collapsible (eg, supraglottic region) are suctioned closed because of negative intraluminal pressure generated during inspiration. These same areas are forced open during expiration. For this reason, disorders that cause supraglottic obstruction cause stridor that is mostly heard on inspiration. Stridor that occurs due to glottic disorders (eg, croup) and trachea disorders (eg, tracheitis) is often biphasic, or heard during both inspiration and expiration.  

Young children who present with stridor require a meticulous evaluation to determine the etiology and, most importantly, to exclude rare life-threatening causes. Although croup is usually a mild, self-limited disease, upper airway obstruction may result in respiratory distress and even death.

Pathophysiology

Acute infectious croup is spread through inhalation of the responsible virus. The initial port of entry is the nose and nasopharynx. The infection spreads and eventually involves the larynx and trachea. Although the lower respiratory tract may also be affected, some authors consider laryngotracheobronchitis a separate entity, with bacterial superinfection as the potential cause.

Inflammation and edema of the subglottic larynx and trachea, especially near the cricoid cartilage, are most clinically significant. Histologically, the involved area is edematous, with cellular infiltration located in the lamina propria, submucosa, and adventitia. The infiltrate contains lymphocytes, histiocytes, plasma cells, and neutrophils. Parainfluenzae virus activates chloride secretion and inhibits sodium absorption across the tracheal epithelium, contributing to airway edema. This is the narrowest part of the pediatric airway. Accordingly, swelling can significantly reduce the diameter, limiting airflow. This narrowing results in the barky cough, turbulent airflow and stridor, and chest retractions. Endothelial damage and loss of ciliary function occurs. A fibrinous exudate partially occludes the lumen of the trachea. Decreased mobility of the vocal cords due to edema leads to the associated hoarseness.

In severe disease, fibrinous exudates and pseudomembranes may develop, causing even greater airway obstruction. Hypoxemia may occur from progressive luminal narrowing and impaired alveolar ventilation and ventilation-perfusion mismatch.

Spasmodic croup (laryngismus stridulus) may be a noninfectious variant of the disorder, with a clinical presentation similar to that of the acute disease but with less coryza. In such cases, subglottic edema occurs without the inflammation typical in viral disease. Although viral illnesses may trigger spasmodic croup, the reaction may be allergic rather than a direct result of infection.

Frequency

United States

Croup is the most common pediatric infection that causes stridor, accounting for approximately 15% of clinic and ED visits for pediatric respiratory infections. In North America, incidence peaks in the second year of life at 5-6 cases per 100 children. Approximately 5% of children experience more than one episode. Croup is most common in late fall and early winter but may be seen at any time of year.

Mortality/Morbidity

Hospitalization rates widely vary among communities, with rates from 1.5-30% and typically averaging 2-5%. Throughout the 1990s, US hospitalizations averaged approximately 41,000 per year but appear to have decreased over the last decade. Fewer than 2% of hospitalized children require intubation. Although exact mortality is unknown, one 10-year study found a mortality rate of less than 0.5% in intubated patients.

Sex

Male-to-female ratio is approximately 1.4:1.

Age

Croup is primarily a disease of infants and toddlers usually younger than 6 years of age, with a peak incidence of 7 and 36 month of age. Although the disease is rare after age 6 years, it may be seen as late as age 12-15 years.

Clinical

History

Croup usually begins with nonspecific respiratory symptoms, including rhinorrhea, sore throat, and cough. Fever is generally low grade (38-39°C) but can exceed 40°C. Within 1-2 days, the characteristic signs of hoarseness, barking cough, and inspiratory stridor develop, often suddenly, along with a variable degree of respiratory distress. Most ED visits occur at night from 10 pm to 4 am, and symptoms are perceived as worsening at night. Symptoms typically resolve within 3-7 days but can last as long as 2 weeks.

Spasmodic croup typically presents at night with the sudden onset of "croupy" cough and stridor. The child may have mild upper respiratory complaints but more often appears completely well prior to the onset of symptoms.

Physical

The physical presentation of croup widely varies. Most children have no more than a croupy cough and hoarse cry. Some may have stridor only upon activity or agitation, whereas others have audible stridor at rest and evidence of respiratory distress. Paradoxically, the severely affected child may have "quiet" stridor secondary to the degree of airway obstruction. The child with croup does not appear toxic.

The child's symptoms range from minimal inspiratory stridor to severe respiratory failure secondary to airway obstruction.1 In mild cases, respiratory sounds at rest are normal; however, mild expiratory wheezing may be heard. Children with more severe cases have inspiratory and expiratory stridor at rest with suprasternal, intercostal, and subcostal retractions. Air entry may be poor. Lethargy and agitation may be a result of hypoxemia. Other warning signs of severe respiratory disease include tachypnea, tachycardia out of proportion to fever, and hypotonia. Children may be unable to maintain adequate oral intake, which results in dehydration. Cyanosis is often a late ominous sign.

Many authors have attempted to devise croup scores to assist the examiner in assessing the degree of respiratory compromise. One of the most commonly cited is the Westley score. Although widely used to evaluate treatment protocols, its clinical efficacy has not been extensively studied. According to the Westley scale, a score of less than 3 represents mild disease; a score of 3-6 represents moderate disease; and a score greater than 6 represents severe disease. The score evaluates the severity of croup by assessing the following 5 factors:

  • Inspiratory stridor
    • None - 0 points
    • Upon agitation - 1 point
    • At rest - 2 points
  • Retractions
    • Mild - 1 point
    • Moderate - 2 points
    • Severe - 3 points
  • Air entry
    • Normal - 0 points
    • Mild decrease - 1 point
    • Marked decrease - 2 points
  • Cyanosis
    • None - 0 points
    • Upon agitation - 4 points
    • At rest - 5 points
  • Level of consciousness
    • Normal - 0 points
    • Depressed - 5 points

Mild disease consists of occasional barking cough, no stridor at rest, and mild or nonexistent suprasternal or subcostal retractions. Moderate disease includes frequent cough, audible stridor at rest, and visible retractions, but little distress or agitation. Severe disease consists of frequent cough, prominent inspiratory (and, occasionally, expiratory) stridor, conspicuous retractions, decreased air entry on auscultation, and significant distress and agitation. Lethargy, cyanosis, and decreasing retractions are harbingers of impending respiratory failure.

Another clinically useful severity assessment table has been developed by the Alberta Clinical Practice Guideline Working Group.2 Using this classification scheme, 85% of children in 21 general emergency departments in Alberta, Canada, were determined to have mild croup, and less than 1% had severe croup. The assessment is as follows:

  • Mild severity - Occasional barking cough, no audible rest stridor, and either mild or no suprasternal or intercostal retractions
  • Moderate severity - Frequent barking cough, easily audible rest stridor, and suprasternal and sternal retractions at rest, with little or no agitation
  • Severe severity - Frequent barking cough; prominent inspiratory and, occasionally, expiratory stridor; marked sternal retractions; and agitation and distress.
  • Impending respiratory failure - Barking cough (often not prominent), audible rest stridor, sternal retractions may not be marked, lethargy or decreased mentation, and often dusky appearance with no supplemental oxygen

Causes

The parainfluenza viruses (I, II, III) are responsible for as many as 80% of croup cases, with parainfluenza I accounting for most episodes and for 50-70% of hospitalizations. 

Other infectious causes of croup include adenovirus, respiratory syncytial virus (RSV), measles, coxsackievirus, rhinovirus, echovirus, reovirus, metapneumovirus, varicella, herpes simplex virus, human bocavirus, coronavirus, and influenza A and B. Influenza A is associated with severe disease. Influenza A has been implicated in children with severe respiratory compromise.

Mycoplasma pneumoniae has been implicated in a few cases.

Differential Diagnoses

Airway Foreign Body
Mononucleosis and Epstein-Barr Virus Infection
Bacterial Tracheitis
Peritonsillar Abscess
Diphtheria
Retropharyngeal Abscess
Epiglottitis
Sarcoidosis
Inhalation Injury
Subglottic Stenosis
Laryngeal Fractures
Vascular Ring, Right Aortic Arch
Laryngomalacia
Measles

Other Problems to Be Considered

Angioneurotic edema
Allergic reaction
Laryngeal web
Laryngeal papillomatosis
Laryngeal hemangioma
Spasmodic croup
Subglottic hemangioma
Vocal cord paralysis
Uvulitis
Laryngeal tuberculosis
Tracheomalacia
Deep space neck infection
Innominate artery compression
Double aortic arch
Aberrant subclavian artery
Pulmonary artery sling
Wegener granulomatosis
Neoplasm (compressing trachea)

Workup

Laboratory Studies

  • The diagnosis of croup is largely clinical, based on the presenting history and physical examination findings.
  • Laboratory test results rarely contribute to the diagnosis. The CBC count is usually nonspecific, although the WBC count and differential may reveal a viral pattern with lymphocytosis. Identification of specific viruses is also not typically necessary but may be useful in determining isolation needs or, in the case of influenza A, deciding whether antiviral therapy is indicated.
  • ABG measurements are unnecessary and do not reveal hypoxia or hypercarbia unless respiratory fatigue ensues.

Imaging Studies

  • Plain films can verify a presumptive diagnosis or exclude other disorders, such as an aspirated foreign body, epiglottitis, bacterial tracheitis, or retropharyngeal abscess.
  • Plain films should not be used as the only means of making a diagnosis and are not required in uncomplicated cases.
  • The posterior-anterior chest radiograph classically reveals a steeple sign, which signifies subglottic narrowing, whereas the lateral view may reveal a distended hypopharynx (ballooning) during inspiration. However, these findings are not observed in as many as 50% of children with croup. Also, a steeple sign may be observed in patients without croup, representing a false positive.

  • Steeple sign on radiograph.

    Steeple sign on radiograph.


Other Tests

  • Although pulse oximetry findings are within the reference range in most patients, such monitoring is helpful to assess the degree of respiratory compromise in severe cases. 
  • Arterial blood gases are unnecessary and show neither hypoxia nor hypercarbia unless respiratory fatigue ensues.

Procedures

  • Laryngoscopy is required only in unusual circumstances (eg, the course of illness is not typical, the child has symptoms that suggest an underlying anatomic or congenital disorder). It may also be required in patients with bacterial tracheitis to obtain the necessary cultures.

Treatment

Medical Care

Any infant who presents with respiratory distress must receive a thorough evaluation to ensure the patency of the airway and maintenance of effective oxygenation and ventilation. 

ED treatment of croup depends on the degree of distress. For example, a child who presents with only a croupy cough may require nothing more than parental reassurance, and the parents may only need education regarding the course of the disease. Any child who presents with respiratory complaints must have a thorough evaluation to ensure the patency of the airway and maintenance of effective oxygenation and ventilation. Infants with severe respiratory distress or compromise require 100% oxygenation with ventilation support initially with a bag-valve-mask device. If the airway and breathing require further maintenance, the patient should be intubated with an endotracheal tube. Intubation should be accomplished with an endotracheal tube that is 0.5-1 mm smaller than predicted.

  • The first rule of management is to keep the child as comfortable as possible, allowing the patient to remain in a parent's arms and avoiding unnecessary painful interventions that may cause agitation and increased oxygen requirements by the child. Persistent crying increases oxygen demands and respiratory muscle fatigue and worsens the obstruction.
  • Careful monitoring of the heart rate, respiratory rate, respiratory mechanics, and pulse oximetry are important to detect early hypoxia.
  • Throughout the 19th and most of the 20th century, cool mist administration was the mainstay of treatment. Hospitals had "croup rooms" filled with mist. Theoretically, mist moistens airway secretions, decreases their viscosity, and soothes the inflamed mucosa. Animal data show that microaerosol inhalation activates mechanoreceptors that produce a reflex slowing of respiratory flow rate and leads to improved airflow. Despite its continued widespread use, little evidence supports the clinical efficacy of cool mist. Randomized studies of children with moderate-to-severe croup revealed no difference in outcome between those who received cool mist and those who did not.3  In addition, the use of hot steam should be avoided because scalding has been reported. Also, mist tents can disperse fungus and molds if not properly cleaned and, more importantly, separates the child from the parent, which usually causes them to be agitated and worsens their symptoms.
  • The current cornerstones of treatment are glucocorticoids and nebulized epinephrine, although steroids have proven beneficial in severe, moderate, and even mild croup. 
  • Corticosteroids are beneficial because of their anti-inflammatory action, whereby laryngeal mucosal edema is decreased. They also decrease the need for salvage nebulized epinephrine. 
    • A single dose of dexamethasone has been shown to be effective in reducing the overall severity of croup if administered within the first 4-24 hours after onset of illness. The long half-life of dexamethasone (54 h) often allows for a single injection. Dexamethasone (0.15 mg/kg) is as effective as 0.3 mg/kg or 0.6 mg/kg in relieving symptoms of mild-to-moderate croup. It has the same efficacy if administered intravenously, intramuscularly, or orally.
    • A single oral dose of prednisolone (1 mg/kg) resulted in more return visits than a single oral dose of dexamethasone (0.15 mg/kg).4
    • Inhaled budesonide has also proven to be effective but is more expensive; in one study, oral dexamethasone resulted in better improvement than nebulized budesonide. 
    • Corticosteroids should not be administered to children with varicella or untreated tuberculosis.
  • Nebulized racemic (mixture of d -isomers and l -isomers) or L-epinephrine is typically reserved for patients in moderate-to-severe distress. It works by adrenergic stimulation, which causes constriction of the precapillary arterioles, thereby decreasing capillary hydrostatic pressure. This leads to fluid resorption from the interstitium and improvement in the laryngeal mucosal edema. Its beta-2-adrenergic activity leads to bronchial smooth muscle relaxation and bronchodilation. Although a child who is symptomatic enough to receive epinephrine may be discharged after at least 3 hours of observation, anyone receiving epinephrine should also be given corticosteroids.
  • Antibiotics are not indicated.
  • Heliox is a metabolically inert, nontoxic gas that is combined with oxygen. It has low viscosity and low specific gravity, which allows for greater laminar airflow through the respiratory tract. Helium decreases the force necessary to move the gas through the airways and decreases the mechanical work of respiratory muscles, which is clinically seen as less respiratory distress.5  Several trials of heliox have demonstrated no advantage over conventional modalities; however, other trials have shown it to be equally effective in moderate-to-severe croup when compared with racemic epinephrine.6,7,8  It has also been shown to improve symptoms in very severe croup that failed to improve with racemic epinephrine.

Medication

Corticosteroids

Although a subject of controversy throughout the 1980s and 1990s, corticosteroids have since become a routine part of ED management of croup. Corticosteroids have shown to decrease hospitalization rates by 86%. Steroids are thought to decrease airway edema via their anti-inflammatory effect. In mild disease, corticosteroids have been proven to reduce the number of children returning to the ED for further treatment. In moderate-to-severe disease, they improve croup scores within 12-24 hours and decrease hospitalization rates. Most trials have used dexamethasone at 0.6 mg/kg (intramuscular or oral), but oral doses as low as 0.15 mg/kg are effective. Oral and intramuscular routes appear equally beneficial. Prednisolone (1 mg/kg) has been proven effective but may be associated with a greater return of children to the ED. 

Inhaled corticosteroids also have demonstrated efficacy, with most trials using budesonide. However, according to most authors, the relative ease, speed, and cost of administration make systemic corticosteroids preferable to nebulized formulations.


Dexamethasone (Decadron)

Several studies have shown improvement in clinical symptoms and croup score in patients who were hospitalized or treated in the ED. Dexamethasone exerts beneficial effect via anti-inflammatory action in which laryngeal mucosal edema is decreased. Onset of action occurs within 6 h for PO and IM. Long pharmacodynamic effect of 36-56 h. No studies have evaluated the effect of multiple doses.

Dosing

Adult

Pediatric

0.15-0.6 mg/kg PO/IM as a single dose; not to exceed 10 mg/dose

Interactions

Coadministration with barbiturates, phenytoin, or rifampin can decrease effectiveness

Contraindications

Documented hypersensitivity; systemic fungal infections; varicella exposure; tuberculosis

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Prolonged use has been associated with adrenal insufficiency, psychosis, immunosuppression, peptic ulcer disease, CHF, anaphylaxis, osteoporosis, pseudotumor cerebri, pancreatitis, nausea, vomiting, dyspepsia, edema, headache, dizziness, mood swings, insomnia, anxiety, hypokalemia, hypertension, hyperglycemia, cushingoid features, menstrual irregularities, ecchymosis, acne, skin atrophy, and impaired wound healing
One case report of a child developing candidal tracheitis after receiving both steroids and antibiotics while hospitalized for croup


Prednisone (Deltasone) or prednisolone (Prelone)

Several studies have shown improvement in clinical symptoms and croup score in patients who were hospitalized or treated in the ED. Corticosteroids exert beneficial effect via anti-inflammatory action in which laryngeal mucosal edema is decreased. In calculating an appropriate prednisone dose, dexamethasone is 6.67 times more potent and has a long half-life of 36-56 h vs a median half-life of 18-36 h for prednisone.

Dosing

Adult

Pediatric

Not established; one randomized controlled trial demonstrated decreased duration of intubation in children receiving prednisolone 1 mg/kg PO q12h until 24 h after extubation; not to exceed 60 mg/24 h

Interactions

Coadministration with barbiturates, phenytoin, or rifampin can decrease effectiveness; coadministration with estrogens can decrease clearance; concurrent use with digoxin may cause digitalis toxicity secondary to hypokalemia

Contraindications

Documented hypersensitivity; systemic fungal infections; tuberculosis; varicella or exposure to varicella; peptic ulcer disease; hepatic dysfunction

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Prolonged use has been associated with adrenal insufficiency, psychosis, immunosuppression, peptic ulcer disease, CHF, anaphylaxis, osteoporosis, pseudotumor cerebri, pancreatitis, nausea, vomiting, dyspepsia, edema, headache, dizziness, mood swings, insomnia, anxiety, hypokalemia, hypertension, hyperglycemia, cushingoid features, menstrual irregularities, ecchymosis, acne, skin atrophy, and impaired wound healing


Budesonide (Pulmicort Respules)

Clinical studies have documented improvement in symptoms and decrease in hospital admissions with nebulized budesonide in children with croup. Corticosteroids exert beneficial effect via anti-inflammatory action in which laryngeal mucosal edema is decreased.

Dosing

Adult

Pediatric

2 mL (0.5 mg) of solution inhaled via nebulizer

Interactions

None reported

Contraindications

Documented hypersensitivity; active bacterial or fungal infection

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Prolonged use may increase the systemic absorption of corticosteroids; hypothalamic-pituitary axis suppression; hyperglycemia; glycosuria

Nebulized vasoconstrictors

Epinephrine stimulates alpha-receptors and beta2-receptors. It constricts the precapillary arterioles, thus decreasing airway edema. Because of the potential adverse effects of tachycardia and hypertension, it is reserved for children with moderate-to-severe disease. The effects of epinephrine are transient, and most trials show alleviation of symptoms for no longer than 2 h. In the 1980s and early 1990s, a rebound phenomenon was thought to occur, necessitating admission of all children who received the drug. However, in recent years, patient discharge after 3-4 hours of observation has become acceptable as long as they have no stridor at rest, normal air entry, normal color, normal consciousness, and have received a dose of steroids.


Epinephrine, racemic (microNefrin) 2.25%

Mixture of dextro and levo isomers. Causes adrenergic stimulation, which constricts precapillary arterioles, thus decreasing capillary hydrostatic pressure. This leads to fluid resorption from the interstitium and improvement in the laryngeal mucosal edema, although its beta2 activity leads to bronchial smooth muscle relaxation.

Dosing

Adult

Pediatric

Administer 2.25% solution for nebulization (dose according to weight listed below) mixed with 3 mL saline:
<20 kg: 0.25 mL
20-40 kg: 0.5 mL
>40 kg: 0.75 mL
May repeat q20-30min

Interactions

Inhaled anesthetics may enhance cardiac irritability; nonselective beta-blockers leave alpha effects unopposed, increasing risk of hypertension and tachycardia

Contraindications

Documented hypersensitivity; angle-closure glaucoma; obstruction of ventricular outflow, as in tetralogy of Fallot

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Adverse effects include tachycardia (discontinue if heart rate >200 bpm), dysrhythmias, palpitations, hypertension, tremor, agitation, nausea, vomiting, headache; randomized controlled trials in children with croup reported no adverse effects, particularly tachycardia; one case report of a previously healthy 11-year-old child who developed ventricular tachycardia after receiving 3 doses in 60 min and was later found to have experienced a small MI


Epinephrine (Adrenalin)

Levo isomer. Stimulates alpha-, beta1-, and beta2-adrenergic receptors, which results in bronchodilatation, increased peripheral vascular resistance, hypertension, increased chronotropic cardiac activity, and positive inotropic effects. Causes alpha-adrenergic receptor–mediated vasoconstriction of edematous tissues, thus reversing upper airway edema.

Dosing

Adult

Pediatric

5 mL (5 mg) of 1:1000 solution diluted in 2 mL saline administered via nebulization; may repeat q20-30min

Interactions

Increases toxicity of beta- and alpha-blocking agents and that of halogenated inhalational anesthetics

Contraindications

Documented hypersensitivity; cardiac arrhythmias; angle-closure glaucoma; during labor (may delay second stage of labor)

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in cardiovascular disease, tachycardia (especially with HR >200 bpm), diabetes mellitus, hyperthyroidism, and cerebrovascular insufficiency

Follow-up

Further Inpatient Care

  • Hospital admission is advised in patients with croup if, after optimal ED management, the child exhibits the following:
    • Cyanosis, hypoxia, or both
    • Depressed sensorium
    • Moderate respiratory distress
    • Stridor at rest
    • Progressive symptoms
    • Poor oral intake, dehydration, or both
  • Hospital admission is also advised if the child is young or if the family is unable to properly care for the child at home or cannot return to the ED if needed.
  • Hospital care is largely supportive, including careful monitoring, supplemental oxygen as needed, and rehydration. Nebulized epinephrine may be administered, and some providers administer additional doses of dexamethasone, although the safety and efficacy of this practice has not been well studied.

Complications

  • Complications are rare. In most series, fewer than 5% of children who present with croup require hospitalization, and fewer than 2% of those who are hospitalized are intubated. Death occurs in approximately 0.5% of intubated patients.
  • Bacterial superinfection may result in pneumonia or bacterial tracheitis. Bacterial tracheitis is a serious, life-threatening infection that can arise after an acute viral respiratory infection.9,10,11,12 The child usually has a mild-to-moderate illness for 2-7 days, but then develops severe symptoms. They are usually toxic in appearance and do not respond well to nebulized epinephrine. Treatment requires close observation, broad-spectrum antibiotics and occasionally endotracheal intubation. The most frequent organism is Staphylococcus aureus, followed by group A streptococcus, Moraxella catarrhalis, Streptococcus pneumoniae, Haemophilus influenzae, and anaerobes.
  • Pulmonary edema, pneumothorax, lymphadenitis, and otitis media have also been reported.
  • An inability to maintain adequate oral intake may lead to dehydration.

Prognosis

  • Prognosis is excellent.
  • Some evidence suggests that hospitalization for croup may be associated with a future development of asthma. In at least one study, children admitted for croup later demonstrated higher levels of bronchial hyperresponsiveness and an allergic response to skin testing.

Patient Education

  • For more information, see eMedicine's patient education article Croup.

Miscellaneous

Medicolegal Pitfalls

  • Patients who receive epinephrine in the ED should be observed for at least 3 hours and should be discharged only if they demonstrate healthy color, air entry, consciousness, and no stridor at rest and have received a dose of corticosteroids.
  • Corticosteroids may be warranted even in children who present with mild symptoms.
  • Although croup is the most common cause of stridor in the pediatric population, other disorders, such as aspirated foreign bodies and epiglottitis, must be considered.

Multimedia

Steeple sign on radiograph.

Media file 1: Steeple sign on radiograph.

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Keywords

croup, barking cough, laryngotracheitis, stridor, laryngotracheobronchitis, spasmodic croup, influenza A, inspiratory stridor, parainfluenza virus 1, parainfluenza virus II, parainfluenza virus III, steeple sign, upper respiratory infection

Contributor Information and Disclosures

Author

Antonio Muñiz, MD, Associate Professor of Emergency Medicine and Pediatrics, University of Texas Medical School at Houston; Medical Director of the Pediatric Emergency Department, Children's Memorial Hermann Hospital
Antonio Muñiz, MD is a member of the following medical societies: American Academy of Emergency Medicine, American Academy of Pediatrics, American College of Emergency Physicians, American Heart Association, American Medical Association, Society for Academic Emergency Medicine, and Southern Medical Association
Disclosure: Nothing to disclose.

Coauthor(s)

Rona E Molodow, MD, JD, Clinical Professor, Department of Pediatrics, Olive View-University of California Los Angeles Medical Center
Rona E Molodow, MD, JD is a member of the following medical societies: American Academy of Pediatrics and American Professional Society on the Abuse of Children
Disclosure: Nothing to disclose.

Germaine L Defendi, MD, MS, FAAP, Associate Clinical Professor, Department of Pediatrics, Olive View-UCLA Medical Center
Germaine L Defendi, MD, MS, FAAP is a member of the following medical societies: Ambulatory Pediatric Association and American Academy of Pediatrics
Disclosure: Nothing to disclose.

Medical Editor

David Jaimovich, MD, Chief Medical Officer, Joint Commission International and Joint Commission Resources
David Jaimovich, MD is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
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Managing Editor

Joseph Domachowske, MD, Professor of Pediatrics, Microbiology and Immunology, Department of Pediatrics, Division of Infectious Diseases, State University of New York-Upstate Medical University
Joseph Domachowske, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American Society for Microbiology, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, and Phi Beta Kappa
Disclosure: Nothing to disclose.

CME Editor

Robert W Tolan Jr, MD, Chief, Division of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine
Robert W Tolan Jr, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa, and Physicians for Social Responsibility
Disclosure: GlaxoSmithKline Honoraria Speaking and teaching; MedImmune Honoraria Speaking and teaching; Merck Honoraria Speaking and teaching; sanofi pasteur Honoraria Speaking and teaching; Baxter Healthcare Honoraria Speaking and teaching

Chief Editor

Russell W Steele, MD, Head, Division of Pediatric Infectious Diseases, Ochsner Children's Health Center; Clinical Professor, Department of Pediatrics, Tulane University School of Medicine
Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, and Southern Medical Association
Disclosure: None None None

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