Single Oral Dexamethasone Dose at Triage
One weight-based oral dose is given as soon as croup is diagnosed.
- 0.6 mg/kg: Typical dose (oral, single dose)
- ~1–2 h: Onset (clinical effect begins)
- 36–72 h: Half-life (biologic activity)
- Oral: Route (or IM if vomiting)
Why a single dose
One dose is enough because dexamethasone has a long biologic half-life.
Absorption and distribution
Rapidly absorbed orally and distributed to inflamed airway tissue.
Glucocorticoid Receptor Anti-Inflammatory Action
Dexamethasone binds cytoplasmic receptors that dampen inflammatory gene expression.
- GR receptor: Target (cytoplasmic, ubiquitous)
- NF-κB inhibition: Key pathway (suppresses cytokines)
- IL-1, IL-6, TNF-α: Cytokines reduced (pro-inflammatory)
- ~25–30×: Potency (vs. cortisol)
Receptor binding cascade
Drug-receptor complex enters the nucleus and alters gene transcription.
Downstream suppression
Fewer inflammatory mediators are produced at the airway wall.
Placeholder: mechanism reduces vascular permeability and mucosal swelling.
Subglottic Mucosal Edema Subsides Over Hours
Airway wall swelling gradually decreases over the following hours.
- ~6 h: Peak effect (post-dose)
- ↑ over time: Airway diameter (as edema falls)
- ↓: Vascular leak (reduced permeability)
- up to 24 h+: Duration (sustained effect)
Timeline of edema decline
Swelling drops steadily as the anti-inflammatory effect builds.
Airflow restoration
Widening subglottic lumen restores easier airflow.
Stridor and Cough Improve as Edema Falls
Clinical croup score improves in parallel with mucosal healing.
- within hours: Westley score drop (placeholder)
- resolves first: Stridor at rest (placeholder)
- persists longer: Barky cough (placeholder)
- improves: Sleep/feeding (placeholder)
Symptom sequence
Stridor and retractions ease before the cough fully resolves.
Monitoring
Clinicians track croup score over the observation period.
Lower Rate of Repeat Emergency Visits
A single dose meaningfully lowers the chance of returning to care.
- substantial: Return-visit reduction (placeholder)
- ↓: Hospitalization (placeholder)
- rare: Repeat dosing needed (placeholder)
- favorable: Overall safety (placeholder)
Population-level benefit
Widespread single-dose use lowers overall return-visit burden.
Placeholder: one dose is now standard of care for croup severity.
Practical implications
Simple single-dose regimen improves adherence and outcomes.