Can hydrocortisone (cortisol replacement) be given to a child with Congenital Adrenal Hyperplasia (CAH) presenting with croup?

Hydrocortisone for Croup in Children with CAH

Yes, hydrocortisone can and should be given to a child with Congenital Adrenal Hyperplasia (CAH) who presents with croup, but the approach differs fundamentally from typical croup management because these children require stress-dose glucocorticoid coverage for any acute illness, not anti-inflammatory doses for airway edema.

Critical Distinction: Stress Dosing vs. Anti-inflammatory Dosing

The key issue here is that children with CAH are already on maintenance hydrocortisone for glucocorticoid replacement 1, 2. When they develop any acute illness—including croup—they require stress-dose hydrocortisone to prevent adrenal crisis, which is a life-threatening emergency 1.

Stress Dosing Protocol for Acute Illness in CAH

• Increase the maintenance hydrocortisone dose to 2-3 times the usual daily dose during acute illness, divided into 3-4 doses throughout the day 1
• For moderate illness like croup, administer hydrocortisone at approximately 30-50 mg/m²/day (roughly 10-15 mg/kg/day), divided every 6-8 hours 3
• If the child cannot take oral medications due to respiratory distress or vomiting, switch immediately to intravenous or intramuscular hydrocortisone at 2 mg/kg every 4-6 hours 3

Why This Matters More Than Typical Croup Treatment

• Children with CAH have impaired cortisol production and cannot mount an appropriate stress response to illness 1
• Failure to provide stress-dose coverage during acute illness can result in adrenal crisis within 8 hours, which carries significant mortality risk 4, 3
• The stress dosing serves primarily as physiologic replacement during illness, not as anti-inflammatory therapy for the airway 5

Practical Management Algorithm

Step 1: Assess Severity and Route of Administration

• If the child can swallow and is not in respiratory distress: Give oral hydrocortisone at 2-3x maintenance dose divided TID or QID 1
• If the child has moderate-severe respiratory distress, stridor at rest, or cannot take oral medications: Switch to parenteral hydrocortisone 2 mg/kg IV/IM every 4-6 hours 3

Step 2: Address the Croup Itself

• The stress-dose hydrocortisone will provide some anti-inflammatory benefit for the airway, but this is secondary 5
• Standard croup therapies (nebulized epinephrine, humidified oxygen) should still be used as clinically indicated
• Do not withhold or reduce stress-dose hydrocortisone even if you're concerned about "too much steroid"—the child needs this for survival, not just symptom management 1

Step 3: Monitor for Adrenal Crisis

• Watch for signs of adrenal insufficiency: hypotension, hypoglycemia, hyponatremia, hyperkalemia 3
• Check blood glucose frequently (every 1-2 hours if severely ill) as hypoglycemia can develop rapidly 3
• Monitor electrolytes, particularly sodium and potassium 3

Step 4: Duration and Weaning

• Continue stress dosing until the child is clinically improved and tolerating oral intake well (typically 2-3 days for croup) 1
• Once recovered, taper back to maintenance dosing over 1-2 days 1
• Never abruptly stop stress dosing—this can precipitate adrenal crisis 4

Common Pitfalls to Avoid

• Do not use dexamethasone (the typical croup medication) as the sole glucocorticoid in a child with CAH, as it lacks mineralocorticoid activity and doesn't provide adequate replacement 3
• Do not delay stress dosing while trying to determine if the child "really needs it"—err on the side of treatment 4, 3
• Do not forget mineralocorticoid replacement (fludrocortisone) should be continued at the usual maintenance dose unless the child is receiving very high-dose hydrocortisone (>100 mg/day), which has intrinsic mineralocorticoid activity 6
• Do not fast the child for more than 6 hours without IV dextrose, as children with CAH are at high risk for hypoglycemia during illness 3

Special Considerations for CAH Patients

• These children are on chronic hydrocortisone therapy (typically 8-12 mg/m²/day divided TID) for baseline replacement 7, 8
• The standard treatment for CAH in children is hydrocortisone, not longer-acting glucocorticoids, to allow for growth and development 2, 8
• Parents of children with CAH should have injectable hydrocortisone at home for emergencies and should be trained in its administration 1

Bottom line: A child with CAH and croup needs stress-dose hydrocortisone (2-3x maintenance) to prevent adrenal crisis, administered orally if possible or parenterally if respiratory distress prevents oral intake. This is physiologic replacement during stress, not optional anti-inflammatory therapy.