• Croup (laryngotracheobronchitis) is an acute viral infection classically characterized by a triad of symptoms: a barking cough, inspiratory stridor, and hoarseness that result from variable degrees of subglottic stenosis.
• Spasmodic croup is characterized by the acute onset of inspiratory stridor, usually occurring at night for several hours and recurring over the next several nights. The child is often not ill or has mild upper respiratory symptoms. It may be a variant of viral laryngotracheobronchitis.

• Human parainfluenza virus type 1, most commonly identified
• Human parainfluenza virus types 2 and 3
• Respiratory syncytial virus (RSV)
• Adenovirus
• Influenza viruses A and B
• Enteroviruses
• Mycoplasma pneumoniae (rare)

• The virus enters the body via respiratory droplets on the epithelium of the nasopharyngeal airway.
• The host defense mechanism is to cause an immune response, resulting in increased mucus production, which leads to airway narrowing.
• Edema and erythema of the mucosa of the subglottic region and vocal cords further narrow the airway.
• Airway narrowing may be severe in the subglottic region because the cricoid cartilage limits the lumenal diameter in this area.
• The process of endothelial damage, swelling, and mucus production may extend to the small airways, with resulting atelectasis.

• Most commonly occurs in the first 3 years of life (6–36 months)
• Peak incidence: second year of life (4.7/100)
• The male:female ratio is 3:2.
• Most prevalent in the late fall and winter
• Fewer children are requiring hospitalization

• Poor oral intake/dehydration
• Hypoxia
• Upper airway obstruction
• Respiratory failure (rare)

• The vast majority of patients does not require hospitalization.
• Almost all patients go on to complete recovery.

• Congenital
  • Tracheoesophageal fistula
  • Foregut duplication
  • Laryngomalacia
  • Tracheomalacia
  • Vocal cord paralysis
  • Arnold-Chiari malformation
  • Vascular ring
  • Laryngeal web
• Infection
  • Epiglottis (although less common since universal HiB vaccine)
  • Bacterial tracheitis
  • Retropharyngeal abscess
  • Adenotonsillitis
  • Diphtheria
  • Pneumonia
• Toxins
  • Foreign-body aspiration
  • Caustic material ingestion (very alkaline products)
  • Smoke inhalation
• Trauma
  • Subglottic edema/stenosis post intubation
  • Laryngeal fracture
• Tumor
  • Papillomatosis
  • Hemangioma
  • Cystic hygroma
  • Lymphoma
  • Rhabdomyosarcoma
  • Thymoma
  • Teratoma
• Genetic/metabolic
  • Hypocalcemia
• Allergic/inflammatory
  • Asthma
  • Angioneurotic edema (anaphylaxis)
  • Spasmodic croup
  • Microaspiration secondary to gastroesophageal reflux

Question: How long have the symptoms been present? Is the process acute or chronic?

Significance: Croup is an acute illness.

Question: Any fever?

Significance: Croup is often associated with fever. If no fever, do not forget foreign-body or caustic ingestions.

Question: When did the stridor begin or occur?

Significance: If the child awakens at night, this supports the diagnosis of croup. If the child is playing at the onset of stridor, consider foreign-body aspiration.

Question: How have the symptoms progressed?

Significance: Ask about URI prodrome, sore throat, change in quality of voice, dysphagia/drooling (consider epiglottitis), dysphonia, particular position of comfort.

Question: Is there a history of previous airway problems or recurrent stridor?

Significance: Recurrence or a prolonged history should lead one to consider subglottic stenosis or gastroesophageal reflux.

• In general, the child with croup is often anxious and ill-appearing. Allow them to sit in a comfortable position and in their caregiver’s (parent’s) lap, this will hopefully reduce the agitation provoked by examination.
• It is important initially to assess level of consciousness, irritability, color, and respiratory distress.
• Vital signs: Check for pulsus paradoxicus (large inspiratory drop in systolic blood pressure because of fall in pleural pressure secondary to airway obstruction).
• What is the preferred position? Sitting in a tripod position with the neck extended to “sniff” is concerning for epiglottis.
• Assess work of breathing, including respiratory rate, nasal flaring, retractions, abdominal breathing, and head bobbing.
• Assess air entry into the chest.
• Listen for audible stridor at rest.
• Listen for the presence of wheezing.
• Observe for drooling.
• Assess the quality of the voice.
• Neck masses or bruising suggest bacterial infection or trauma.
• The Croup Score (as developed by Westley, et al. and modified by Super, et al.) is utilized by many clinicians to describe the severity of symptoms (see table Severity Score of Croup Patients).

• In general, laboratory tests are not required to make this diagnosis.
• Blood testing, such as arterial blood gas or complete blood count with differential, is not helpful in diagnosing croup. In fact, the pain and fear of the testing will likely heighten the child’s anxiety and worsen respiratory distress.

• Most do well with conservative management at home or, much less commonly, after a short stay in the emergency department.
• In the child with impending respiratory failure, prompt intubation and direct visualization of the airway in the operating room is imperative. Do not wait for x-rays to confirm a diagnosis.
• Humidity: humidified air delivered by tent or face mask in the hospital, or by cool mist vaporizer or a steam-filled bathroom at home. In the cold of winter, walking outside into the crisp, cold air is often very effective.
• Racemic epinephrine: A nebulized, racemic epinephrine treatment offers immediate reduction in swelling of the laryngeal airway in children who present in extreme respiratory distress or in whom humidified air does not improve stridor (croup score >3) after 20 to 30 minutes. Dose: 0.5 mL of 2.25% solution in 2.5 mL normal saline delivered via nebulizer.
• Steroids: Utilized in the emergency room and inpatient settings, steroids have resulted in decreased length of hospital stay and decreased number of admissions due to croup. Dexamethasone (half-life 36–54 hours) given intramuscularly (IM) in the setting of moderate-to-severe croup (croup score >3): 0.6 mg/kg as a single dose is the recommended dose.

• In most cases, the illness is self-limited, lasting 3 to 5 days.
• A “rebound phenomenon” with worsening of stridor and respiratory distress after initial relief with the racemic epinephrine treatment may be seen up to 2 hours posttreatment in some patients. Several studies have shown that children can be safely discharged home 3 to 4 hours after racemic epinephrine treatment.

Q: Should all children with croup receive steroids in an attempt to prevent hospitalization?
A: The literature certainly is convincing for the use of IM dexamethasone in combination with mist and racemic epinephrine for children with moderate-to-severe croup scores. There is no evidence to date, however, supporting the use of steroids in the mild cases as a preventative measure. Steroids have not been shown to shorten the course of the illness; however, the severity is diminished.

Q: Do children who receive racemic epinephrine for croup require hospitalization?
A: No. Several studies now have shown that after a 3- to 4-hour period of observation and dexamethasone, children can be safely discharged home. Any rebound effects should occur within the first 2 hours.

Q: Do steroids need to be given IM?
A: The bioavailability of steroids is excellent, whether IM or orally administered. The half-life of dexamethasone is much longer (36–54 hours) than that of prednisone (12–36 hours). With croup, many patients have poor oral intake exacerbated by respiratory distress. Gastric irritation with enteral dosing is not uncommon, making compliance poor. Most of the large studies evaluating croup and steroid dosing have looked at the IM dosing of dexamethasone. Oral steroid dosing for croup has not been established.

Q: What’s new in the treatment of croup?
A: Budesonide, a glucocorticoid available in a nebulized form, has recently been used successfully in the treatment of croup. The ease of administration and rapid onset of action make it an exciting prospect for management. This medication is, however, not available in the United States.

Connors K, Gavula D, Terndrup T. The use of corticosteroids in croup: A survey. Pediatr Emerg Care 1994;10(4):197–199.

Geelhoed GC. Sixteen years of croup in a western Australian teaching hospital: effects of routine steroid treatment. Ann Emerg Med 1996;28(6):621–626.

Kairys SW, Olmstead EM, O’Connor GT. Steroid treatment of laryngotracheitis: a meta-analysis of the evidence from randomized trials. Pediatrics 1989;83(5):683–693.

Klassen TP, Feldman ME, Watters LK, et al: Nebulized budesonide for children with mild-to-moderate croup. N Engl J Med 1994;331(5):285–289.

Kunkel NC, Baker MD. Use of racemic epinephrine, dexamethasone, and mist in the out-patient management of croup. Pediatr Emerg Care 1996;12(3):156–159.

Ledwith CA, Shea LM, Mauro RD. Safety and efficacy of nebulized racemic epinephrine in conjunction with oral dexamethasone and mist in the outpatient treatment of croup. Ann Emerg Med 1995;25(3):331–337.

Macdonald WBG, Geelhoed GC. Management of childhood croup. Thorax 1997;52:757–759.

Marx A, Torok TJ, Holman RC, Clarke MJ, Anderson LJ. Pediatric hospitalizations for croup (laryngotracheobronchitis): biennial increases associated with human parainfluenza virus 1 epidemics. J Infect Dis 1997;176:1423–1427.

Steele DW, Santucci KA, Wright RO, Natarajan R, McQuillen KK, Jay GD. Pulsus paradoxus: an objective measure of severity in croup. Am J Respir Crit Care Med 1998;157:331–334.

Super DM, Cartelli NA, Brooks LJ, Lembo RM, Kumar ML. A prospective randomized double-blind study to evaluate the effect of dexamethasone in acute laryngotracheitis. J Pediatr 1989;115:323–329.

Waki EY, Madgy DN, Belenky WM, Gower VC. The incidence of gastroesophageal reflux in recurrent croup. Int J Pediatr Otorhinolaryngol 1995;32:223–232.

Westley CR, Cotton EK, Brooks JG: Nebulized racemic epinephrine by IPPB for the treatment of croup. Am J Dis Child 1978;132:484–487.