What is the role of prednisolone in the treatment of anaphylaxis?

Role of Prednisolone in Anaphylaxis

Prednisolone and other corticosteroids are adjunctive medications in anaphylaxis that should never be used as first-line treatment or as a substitute for epinephrine, but they are commonly administered to potentially prevent biphasic or protracted reactions despite limited evidence supporting this practice. 1

Primary Treatment Principle

• Epinephrine is the only first-line treatment for anaphylaxis and must be administered immediately via intramuscular injection (0.01 mg/kg, maximum 0.5 mg in adults) in the lateral thigh. 1, 2, 3
• Corticosteroids have no role in acute symptom management because their onset of action is 4-6 hours, far too slow for the rapid and potentially fatal nature of anaphylaxis. 1
• Antihistamines and corticosteroids must never be administered before or in place of epinephrine. 1, 3

When to Administer Corticosteroids

If corticosteroids are given, administer intravenous methylprednisolone 1-2 mg/kg every 6 hours (or oral prednisone 0.5 mg/kg for milder reactions) after epinephrine has been administered. 1, 2, 4

The rationale for corticosteroid use includes:

• Potentially preventing biphasic anaphylaxis (recurrence of symptoms after initial resolution), which occurs in up to 20% of cases. 1
• Possibly preventing protracted anaphylaxis (prolonged symptoms). 1, 5
• Providing additional benefit for patients with asthma or those recently treated with corticosteroids. 1

Evidence Quality and Controversy

The evidence supporting corticosteroid use in anaphylaxis is notably weak:

• No randomized controlled trials exist demonstrating that corticosteroids prevent biphasic reactions or improve outcomes in anaphylaxis. 6, 7
• A 2017 systematic review found that corticosteroids appear to reduce hospital length of stay but did not reduce emergency department revisits. 6
• Another 2017 review concluded that biphasic reactions are more likely with delayed epinephrine administration, not prevented by corticosteroids, and recommended against routine corticosteroid use due to lack of compelling evidence. 7
• Despite weak evidence, corticosteroid use in emergency anaphylaxis treatment averages 68% (range 48-100%) across studies. 6

Special Indication: Idiopathic Anaphylaxis

Corticosteroids have a proven role in preventive management of frequent idiopathic anaphylaxis (not acute treatment):

• Prednisone controls recurrent episodes and can induce remission in patients with frequent idiopathic anaphylaxis. 8, 9
• Some patients require maintenance prednisone therapy at threshold doses ranging from 15-65 mg every other day to prevent recurrent episodes. 8
• This preventive use substantially reduces hospitalizations and emergency visits. 9

Practical Dosing Protocol

When corticosteroids are administered for anaphylaxis:

• Intravenous route: Methylprednisolone 1-2 mg/kg every 6 hours or hydrocortisone equivalent. 1, 2, 4
• Oral route: Prednisone 0.5 mg/kg for milder attacks. 1, 4
• Duration: Treatment should be stopped within 2-3 days, as all reported biphasic reactions occur within 3 days (average 11 hours). 1, 2

Critical Pitfalls to Avoid

• Never delay epinephrine administration to give corticosteroids first—this has been associated with fatalities and higher risk of biphasic reactions. 2, 3
• Do not use corticosteroids alone without epinephrine, as they lack vasoconstrictive, bronchodilatory, inotropic, and mast cell stabilization properties. 1
• Do not rely on corticosteroids to prevent biphasic reactions—the most important factor is timely epinephrine administration. 7
• Recognize that corticosteroids are ineffective for acute cardiovascular collapse, bronchospasm, or hypotension. 1

Observation Period

• After anaphylaxis treatment (including corticosteroids), observe patients for at least 6-24 hours depending on severity, as biphasic reactions can occur up to 72 hours later. 2, 3
• The risk of biphasic reaction is higher in patients requiring more than one dose of epinephrine. 2

Bottom Line

While corticosteroids are widely used in anaphylaxis management based on empiric practice and theoretical benefit, their routine use remains controversial given the lack of high-quality evidence. 1, 6, 7 However, their use appears safe with no documented adverse outcomes in emergency settings, and they may provide benefit in severe or prolonged cases, particularly in patients with asthma or those on chronic corticosteroid therapy. 1, 6 The key principle remains unchanged: epinephrine first, corticosteroids as adjunctive therapy only. 1, 3