Advice after your nerve block for surgery
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Contrast Medium - Post Contrast Reaction
Introduction
This leaflet is for people who have developed an allergic reaction following the injection of contrast media (sometimes called dye). It provides information about what has occurred, what actions have been taken and what to look out for when at home.
What happened?
Like for all medications, on rare occasions, some patients have an allergic or sensitivity reaction to the contrast media that has been given. Mild symptoms are seen in up to one percent of patients and severe symptoms are even rarer. For the majority of such patients, the reaction is mild and any symptoms (including flushing, nausea, itching, vomiting, headache and a mild rash / hives) will resolve quickly with little or no medical help. Almost all contrast reactions that are severe occur within 20 minutes of administration.
Treatment
The radiology team have given you the recommended treatment for the type of reaction that you have experienced. A range of different actions or treatment may have taken place. This includes observing you for a period of time to ensure that your reaction is mild and that you do not need any further treatment. Alternatively, you may have been administered oral or intravenous medication to help relieve the symptoms of the suspected allergic reaction.
What should I watch out for?
There is a possibility of delayed signs and symptoms following a suspected reaction. These reactions can occur between one hour to one week after the contrast administration. These are commonly non-severe skin symptoms such as rashes, hives and swelling.
If you have been issued with any medication after your reaction, it is important that you keep it with you and have it available. Please ensure that you have someone around to either check in on you or monitor you for the next 24 hours. This is because you may experience drowsiness depending on the type of medication given. If your symptoms re-occur or worsen after leaving the hospital, please consult NHS 24 (telephone 111), your GP or Accident & Emergency and take this information with you.
What should I do in the future?
If you are referred for any future examinations with contrast media / dye, it is important to tell your doctor and GP about your previous contrast reaction. This way, your clinical information can be updated to reflect what has happened. There is an approximate tenfold increase in reactions to contrast media following a previous reaction, so it is usual to avoid contrast media in the future. If you attend any Radiology Department for any scans or procedures in the future, please let them know of your contrast allergy.
Additional Information
For more information about this, you can look at the following links:
NHS Information: Anaphylaxis
Royal Australian and New Zealand College of Radiologists Iodinated Contrast Guidelines
Contact us
If you have any queries relating to this information, please contact the Radiology service.
About this information
Service:
Radiology
Reference:
PILS.3
Approval date:
24 April 2024
Review date:
24 April 2027
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Important note
This page provides general information only. It is developed by clinical staff and is reviewed regularly every 3 years for accuracy. For personal advice about your health, or if you have any concerns, please speak to your doctor.