Hydrocortisone Dosage for Allergic Reactions
For acute allergic reactions with urticaria or moderate infusion-type reactions, administer hydrocortisone 200 mg IV. 1
Dosing by Clinical Scenario
Anaphylaxis and Severe Allergic Reactions
- Hydrocortisone 200 mg IV (or IM if IV access unavailable) for adults over 12 years 1
- 100 mg IV/IM for children 6-12 years 1
- 50 mg IV/IM for children 6 months to 6 years 1
- 25 mg IV/IM for infants under 6 months 1
Critical caveat: Hydrocortisone is an adjunctive therapy in anaphylaxis—epinephrine remains the first-line treatment and must not be delayed. 1 Corticosteroids do not reverse acute bronchospasm or hypotension but help prevent biphasic reactions. 1
Mild to Moderate Infusion Reactions (Urticaria, Flushing)
- Hydrocortisone 200 mg IV if symptoms do not improve or worsen after 15 minutes of observation 1
- Administer alongside second-generation antihistamines (cetirizine 10 mg IV/PO or loratadine 10 mg PO) for urticaria 1
- Avoid first-generation antihistamines (diphenhydramine) as they can paradoxically worsen hypotension and tachycardia 1
Administration Guidelines
Route and Timing
- IV administration preferred over 30 seconds to 10 minutes depending on dose 2
- For doses ≥500 mg, infuse over 30-60 minutes and observe patient for equal duration afterward 3
- IM injection acceptable when IV access unavailable 1
Preparation
- Reconstitute with ≤2 mL Bacteriostatic Water for Injection 2
- For IV infusion, may dilute in 100-1000 mL of 5% dextrose or normal saline 2
- Do not mix with other solutions due to physical incompatibilities 2
Duration and Monitoring
Treatment Course
- Single dose typically sufficient for isolated allergic reactions 1
- For severe reactions requiring ongoing therapy, continue only until patient stabilizes (usually ≤48-72 hours) 2
- Taper gradually if therapy extends beyond 48-72 hours rather than stopping abruptly 2
Special Monitoring
- Watch for hypernatremia if high-dose therapy continues beyond 48-72 hours 2
- Observe asthmatics and hemodynamically unstable patients more closely, as they may be at higher risk for adverse reactions 3
Common Pitfalls to Avoid
Do not rely on hydrocortisone alone for acute anaphylaxis—it has no immediate effect on airway edema or hypotension. 1 Epinephrine 0.5 mg IM (or 0.3 mg for smaller adults) into the anterolateral thigh must be given first. 1
Avoid rapid IV push of doses ≥500 mg—this increases risk of cardiovascular collapse. 3 Infuse over 30-60 minutes instead. 3
Do not use corticosteroids as premedication for routine procedures unless the patient has multiple drug allergies, prior severe reactions, or asthma. 1 Routine premedication is controversial and not evidence-based. 1
Cross-Reactivity Considerations
Patients can paradoxically develop allergic reactions to corticosteroids themselves, most commonly with methylprednisolone and hydrocortisone. 3 If a patient has documented hydrocortisone allergy, intradermal skin testing may identify alternative corticosteroids that can be tolerated. 3 Systemic hydrocortisone can trigger cutaneous reactions at sites of previous allergic dermatitis in presensitized individuals. 4