What is the role of glucocorticoids (corticosteroids) in managing contrast media (contrast agent)-induced allergic reactions?

From the Guidelines

Glucocorticoids are recommended for preventing contrast-related allergic reactions in patients with a history of moderate to severe reactions to contrast media, as stated in the 2011 ACCF/AHA/SCAI guideline for percutaneous coronary intervention 1. The standard premedication regimen consists of oral prednisone 50 mg given at 13 hours, 7 hours, and 1 hour before contrast administration (total of 150 mg), along with diphenhydramine 50 mg orally or intravenously 1 hour before the procedure. For emergency situations when the full oral regimen isn't possible, intravenous methylprednisolone 40 mg every 4 hours until contrast administration, with the last dose given immediately before the procedure, can be substituted. Adding an H2-blocker such as famotidine 20 mg may provide additional benefit. These medications work by suppressing the immune response that causes allergic reactions, with glucocorticoids inhibiting multiple inflammatory pathways while antihistamines block histamine-mediated symptoms. However, more recent guidelines, such as the 2020 practice parameter update, systematic review, and grading of recommendations, assessment, development and evaluation (GRADE) analysis, suggest against routinely administering glucocorticoids and/or antihistamines to prevent anaphylaxis in patients with prior radiocontrast HSRs when readministration of a low- or iso-osmolar, nonionic RCM agent is required, with a strength of recommendation of conditional and certainty of evidence of very low 1. This premedication approach reduces the risk of repeat reactions, though it doesn't eliminate the risk entirely. Patients should still be monitored during and after contrast administration, and emergency medications and equipment should be readily available. It's also important to note that the incidence of anaphylactoid reactions to contrast media is 1%, and the incidence of severe reactions may be as low as 0.04% 1. In patients with a prior history of allergic reactions to shellfish or seafood, anaphylactoid prophylaxis for contrast reaction is not beneficial 1. Ultimately, the decision to use glucocorticoids for contrast-related allergy should be made on a case-by-case basis, taking into account the individual patient's history and risk factors. The most recent and highest quality study, the 2020 practice parameter update 1, should be prioritized when making this decision. Key points to consider include:

• The patient's history of contrast-related allergic reactions
• The severity of previous reactions
• The type of contrast media being used
• The availability of emergency medications and equipment
• The patient's overall health status and risk factors for anaphylaxis. In general, the use of glucocorticoids for contrast-related allergy should be guided by the most recent and highest quality evidence, with a focus on minimizing the risk of morbidity, mortality, and reducing the impact on quality of life.

From the Research

Glucocorticoids for Contrast-Related Allergy

• The use of glucocorticoids for contrast-related allergy is a topic of interest, with several studies investigating their efficacy and safety 2, 3, 4, 5, 6.
• A case study published in 2006 reported the successful desensitization of a patient with a history of radiocontrast-induced anaphylactoid reaction and corticosteroid allergy using hydrocortisone 2.
• Another study published in 2013 discussed the protocols used to prevent or reduce allergy-type reactions to iodinated contrast media, including the use of glucocorticoids as premedication 3.
• However, there is also evidence that glucocorticoids can cause allergic reactions, including anaphylaxis, in some individuals 4, 5.
• A review published in 2020 highlighted the importance of identifying patients at high risk for hypersensitivity reactions to contrast agents and dyes, and discussed the use of skin testing and premedication to prevent or reduce the occurrence of these reactions 5.
• A study published in 2017 proposed a stratified premedication strategy for the prevention of contrast media hypersensitivity in high-risk patients, which included the use of glucocorticoids such as methylprednisolone 6.

Key Findings

• Glucocorticoids can be used as premedication to prevent or reduce the occurrence of allergy-type reactions to iodinated contrast media 3, 6.
• However, glucocorticoids can also cause allergic reactions, including anaphylaxis, in some individuals 4, 5.
• Skin testing and challenge testing can be used to identify patients who are allergic to specific glucocorticoids and to select alternative agents that are safe for future use 2, 4, 5.
• A stratified premedication strategy based on the severity of previous reactions can be effective in reducing the risk of breakthrough reactions in high-risk patients 6.