Dorothy FarrarContrast agent allergy
In the case of a contrast agent allergy, the sick person suffers from an allergy to various types of contrast agents that are used in various medical examination procedures. Contrast agents are often used, for example, in magnetic resonance imaging or computed tomography. Contrast media are also sometimes used in ultrasound.
What is a contrast medium allergy?
In the context of contrast agent allergy, patients develop an allergic reaction to certain components of the contrast agent. For example, allergies to the iodine contained in contrast media are particularly common . The typical symptoms of an allergic reaction are caused by an irritation of the immune system .
In numerous cases, contrast media enter the human organism via an injection. The substance spreads throughout the body with the blood and accumulates in areas of particularly high blood flow. In this way, the contrast medium helps to identify tumors or inflammation , for example . The examination is problematic if the patient suffers from a contrast medium allergy.
causes
A contrast agent allergy arises when the immune system of the affected person is sensitized to certain allergenic substances. This raises the question of which substance in the contrast agent a patient is allergic to. In numerous cases, people suffer from an allergy to the iodine contained in many contrast media. As a result, the symptoms associated with examinations using contrast media are associated with an iodine allergy. However, allergies to substances other than iodine are also possible in the case of a contrast agent allergy.
In addition, certain groups of people are particularly at risk of developing an allergy to contrast media. This includes, for example, patients suffering from asthma. Because these people have an increased tendency to allergies. Other allergy sufferers who are already allergic to various substances also tend to develop an allergy to contrast media more often. This applies, for example, to people with pollen or food allergies. In addition, neurodermatitis sufferers are particularly at risk of developing an allergy to contrast media. Concomitant administration of beta-blockers during examinations with contrast media also increases the likelihood that the affected person will develop an allergy to contrast media.
symptoms and course
Typical symptoms:
In most cases, the symptoms of a contrast agent allergy appear at the earliest a few hours after the examination with the responsible contrast agent. Usually, however, the symptoms only appear days after the administration of the contrast medium. The first signs of the contrast medium allergy often appear on the skin of the sick patient. Redness, swelling and rashes on the skin are characteristic. The affected areas of skin are usually very itchy. In addition, some allergy sufferers suffer from dizziness, nausea and headaches.
It is also possible that the symptoms appear less than an hour after the administration of the allergenic substance. In this case, an immediate-type contrast agent allergy is present. The treating staff and the radiology department must be informed immediately of the signs of an allergic reaction. In addition to mild symptoms of a contrast agent allergy, more severe symptoms are also possible. The patients suffer, for example, from an increased pulse rate, vomiting, shortness of breath and edema. The mucous membranes swell and people develop what is known as hives. Due to the swelling, there is a risk that patients will suffocate. In the worst case, people suffer anaphylactic shock.
Diagnose
If there are more indications of a contrast agent allergy, immediate consultation with a doctor is indicated. People usually first contact their family doctor or the radiologist responsible for the examination with the contrast agent. In many cases, you will be referred to an allergist or dermatologist.
As part of an anamnesis, the doctor discusses the symptoms of the allergy with the patient. In doing so, the treating doctor asks in particular about the circumstances accompanying the symptoms. A connection to the administration of contrast media that took place a few days earlier is usually found relatively quickly. If the suspicion of a contrast agent allergy is also substantiated on the part of the doctor, he uses appropriate test procedures for diagnosis.
In order to diagnose the contrast agent allergy, a so-called skin prick test is usually used. The forearm is slightly superficially injured. The doctor applies the respective allergens to the irritated areas. Based on the reaction, a diagnosis of contrast agent allergy can be made.
In the skin prick test, the immediate type of contrast agent allergy can be determined. To diagnose the late type, a patch test is performed using a patch. After two to three days, the skin reaction is checked and the contrast medium allergy is diagnosed. In principle, an intravenous provocation test is also possible. However, this is riskier than the other two test methods.
complications
A contrast agent allergy can sometimes cause complications if the person concerned repeatedly comes into contact with the allergen. In addition to the general symptoms, i.e. nausea, diarrhea and vomiting as well as skin irritation and circulatory problems, anaphylactic shock can also occur. A contrast agent allergy therefore harbors the same risks as other allergies. However, since contact with contrast media cannot always be avoided, there is an increased risk of allergic reactions.
For example, complaints can arise during a medical examination if the practice has no alternative means available or if an X-ray examination has to be carried out. Then there is at best the possibility of administering a drug to the affected person as a preventative measure, which suppresses the allergic reaction. The treatment of contrast medium allergy does not involve any major risks. An allergy test is usually carried out, which under certain circumstances can already cause a strong allergic reaction. Drug administration is always associated with certain side effects. Asthmatics and patients with multiple allergies are particularly at risk for possible side effects.
treatment and therapy
In the context of an allergy to contrast media, anaphylactic shock is possible, which poses an acute threat to the life of the allergic person. Therefore, an emergency doctor must be called immediately, who will treat the patient with cortisone and adrenaline if necessary.
The blood pressure drops sharply and may lead to a failure of the circulatory system. If the anaphylactic shock occurs in connection with an examination, it must be stopped immediately. The patient is usually given antihistamines and, in some cases, supplemental oxygen.
If an examination with contrast media is indispensable despite an existing allergy to contrast media, appropriate precautions must be taken. The patient receives cortisone and often antihistamines in advance. In this way, the allergic reaction can be prevented to a certain extent.
prevention
In principle, if an allergy is present, the trigger (allergen) for the allergic reaction should be avoided as consistently as possible. If there is no alternative, allergy-inhibiting medication (antihistamines) must be administered in consultation with the doctor.
Hello and welcome to my Health Guide & Encyclopedia! My name is Dorothy Farrar, and I'm the founder and main author of this platform.
My passion for health and wellness started at a young age when I became interested in the connection between the food we eat and the way we feel. This fascination led me to study nutrition and dietetics in college, where I learned about the importance of a balanced diet and the impact of various nutrients on the body.