What are the diagnostic criteria and treatment options for croup in a pediatric patient, likely between 6 months and 5-6 years old, presenting with symptoms such as barking cough, hoarse voice, and stridor?

Diagnosis of Croup

Croup is a clinical diagnosis based on the characteristic triad of barking cough, hoarse voice, and inspiratory stridor, typically occurring in children 6 months to 5-6 years of age, and does not require laboratory studies or radiographic imaging in straightforward cases. 1, 2

Clinical Presentation

The diagnosis relies on recognizing the distinctive clinical features:

• Barking cough (often described as "seal-like") is the hallmark symptom 3, 2, 4
• Inspiratory stridor resulting from upper airway obstruction at the level of the larynx and trachea 2, 4
• Hoarse voice due to laryngeal inflammation 3, 4
• Respiratory distress with variable severity, including use of accessory muscles 1
• Low-grade fever may be present but is not required for diagnosis 2
• Sudden onset of symptoms, typically without significant antecedent respiratory symptoms 1

The median age of presentation is 23 months, with 63% being male patients 1

Severity Assessment

Immediate assessment should focus on key severity indicators 1:

• Ability to speak/cry normally
• Respiratory rate and heart rate
• Presence of stridor at rest (indicates moderate-to-severe disease)
• Use of accessory muscles
• Oxygen saturation
• Life-threatening signs: silent chest, cyanosis, fatigue/exhaustion, or poor respiratory effort 1

Diagnostic Studies

Radiographic studies and laboratory tests are generally unnecessary and should be avoided unless there is concern for an alternative diagnosis. 1

• Viral cultures and rapid antigen testing have minimal impact on management and are not routinely recommended, as croup is most commonly caused by parainfluenza viruses but identifying the specific pathogen does not alter treatment 1, 2, 4
• Lateral neck radiographs should not be relied upon for diagnosis, as clinical assessment is more important 1
• Laryngoscopy should be reserved for patients in whom alternative diagnoses are suspected 2

Differential Diagnoses to Exclude

Critical alternative diagnoses that require different management include 1:

• Bacterial tracheitis - consider if patient fails to respond to standard croup treatment 1
• Foreign body aspiration - distinct presentation without viral prodrome 1
• Epiglottitis - though rare in the post-Hib vaccine era 2
• Retropharyngeal or peritonsillar abscess 1
• Subglottic hemangioma - particularly in infants with large cutaneous lesions in "beard" distribution who present with biphasic stridor and barky cough often mistaken for croup 5

Special Consideration: Recurrent Croup

Recurrent episodes (two or more per year) warrant consideration of underlying conditions 1, 6:

• Asthma should be considered, especially if cough worsens at night, episodes are triggered by exercise or irritants, or there is a family history of asthma or atopy 1
• Anatomic abnormalities - flexible bronchoscopy should be performed in cases of severe or persistent symptoms not responding to standard treatment, with up to 68% of infants with stridor having concomitant lower airway abnormalities 1
• Gastroesophageal reflux - consider if there is vomiting or feeding difficulties 1

Common Pitfalls to Avoid

• Do not perform blind finger sweeps in suspected foreign body aspiration, as this may push objects further into the pharynx 1
• Do not order routine imaging in typical presentations, as this delays treatment and exposes children to unnecessary radiation 1, 2
• Do not confuse with asthma - avoid empirical asthma treatment unless other features consistent with asthma are present 1