Is cephalexin safe for an 8‑year‑old child with primary adrenal insufficiency (Addison’s disease) and a skin infection, and what glucocorticoid stress‑dose adjustments are required?

Cephalexin Safety in an 8-Year-Old with Primary Addison's Disease and Skin Infection

Cephalexin is safe and appropriate for treating skin infections in children with primary adrenal insufficiency, but you must implement stress-dose glucocorticoid supplementation during the infection to prevent adrenal crisis. 1, 2

Antibiotic Safety

• Cephalexin has no direct contraindications or interactions with adrenal insufficiency or glucocorticoid replacement therapy. 3
• Cephalexin achieves cure rates of 90% or higher for streptococcal and staphylococcal skin infections in children, with generally mild and infrequent side effects. 3
• The suspension formulation is well-tolerated by young children, and the antibiotic is absorbed high in the intestinal tract without disturbing lower bowel flora. 4
• Children may require higher doses per kilogram than adults due to greater body water turnover, but this is unrelated to adrenal status. 4

Critical Glucocorticoid Stress-Dose Management

The skin infection itself constitutes physiological stress requiring immediate glucocorticoid dose adjustment—failure to provide stress dosing carries a very high risk of precipitating adrenal crisis. 2, 5, 6

Stress-Dosing Algorithm for This Child

• Double the child's usual daily maintenance hydrocortisone dose immediately and continue doubled dosing throughout the entire duration of the infection and for 24-48 hours after complete symptom resolution. 2, 5
• If the child's usual regimen is hydrocortisone 10 mg in the morning and 5 mg in the afternoon (typical for an 8-year-old), increase to 20 mg morning and 10 mg afternoon. 5
• If the child develops fever, vomiting, or inability to take oral medications, escalate immediately to parenteral hydrocortisone 100 mg IV or IM bolus without delay. 2, 5

When to Escalate to Emergency Dosing

• Severe illness indicators requiring immediate 100 mg IV/IM hydrocortisone bolus: vomiting (inability to retain oral medications), hypotension, altered mental status, severe weakness, or signs of sepsis. 2, 5
• After the initial 100 mg bolus, continue with either hydrocortisone 100 mg IV every 6-8 hours or a continuous infusion of 200 mg/24 hours until the child is stable and able to take oral medications. 2, 5
• For children, weight-based dosing of 2 mg/kg IV every 4-6 hours is an alternative to the adult 100 mg dose, though the 100 mg bolus is standard even in pediatrics for severe stress. 1, 5

Common Pitfalls to Avoid

• Never delay stress-dose steroids while waiting to assess infection severity—infections precipitate approximately 50% of adrenal crises in patients with adrenal insufficiency. 6
• Do not assume the child's baseline hydrocortisone dose is sufficient during infection—even "mild" skin infections constitute physiological stress requiring dose escalation. 2, 5
• Ensure the child continues fludrocortisone (mineralocorticoid) at the usual dose during stress dosing, as primary adrenal insufficiency requires both glucocorticoid and mineralocorticoid replacement. 5, 7
• Hospital ward staff commonly omit or under-dose glucocorticoids—explicitly document stress-dosing instructions and educate all caregivers. 6

Patient/Family Education Requirements

• The family must understand that any infection requires immediate doubling of hydrocortisone and should have written instructions for stress dosing at home. 2, 5
• The child should have emergency injectable hydrocortisone (100 mg) available at home for use if vomiting prevents oral intake. 5
• Ensure the child wears a medical alert bracelet indicating primary adrenal insufficiency. 5
• Teach recognition of adrenal crisis symptoms: severe weakness, confusion, abdominal pain, vomiting, and hypotension. 5

Monitoring During Treatment

• Monitor for signs of inadequate stress dosing: persistent fatigue, nausea, postural hypotension, or hypoglycemia. 5
• Check blood glucose if the child appears unwell, as hypoglycemia is a common manifestation of insufficient glucocorticoid coverage in children with adrenal insufficiency. 1, 5
• Do not reduce the doubled hydrocortisone dose until 24-48 hours after complete resolution of infection symptoms. 2, 5