Cross-allergy to medicines

Not looking at the fact that cross-allergy to medicines is rare, it presents a real danger to human life. How can a cross-sectional allergic reaction to drugs be recognized in time, who is at an increased risk of developing severe allergy to drug therapy? This will be discussed below.

With the help of modern medicines, many serious diseases can be cured and a number of chronic diseases can be prevented, disability and even death can be avoided. At the same time, everyone knows that any medicine can have a side effect. It should be understood that not all side effects can be considered an allergic reaction. Many of them are associated with the components of the drug and the mechanisms of its action. So, for example, puffiness and fluid accumulation happens with taking medications to lower blood pressure, nausea and vomiting are often caused by certain antibiotics, and headache and attention problems result from the use of psychotropic medications.

How is the drug allergenic?

The typical allergic reaction is as follows: reddening of the skin and blush, severe itching, rash appearance in the form of red prominent spots (urticaria), swelling of the eyelids and lips, shortness of breath and wheezing (asthma attacks), problems with voice and hoarseness (with swelling of the larynx) low blood pressure, loss of consciousness and death. A rarely encountered cross immuno-allergic reaction occurs 7-10 days after taking the drug in the form of severe pain, joint inflammation, fever, skin rash and malfunction in the kidneys and liver. But not all side effects are associated with an allergic reaction - some are caused by the composition of the drug or the mechanism of its action.

Dependence of the appearance of an allergic reaction

1. From the preparation

The patient's condition is affected by its composition, the mechanism of absorption into the blood, the duration of the course of treatment and the frequency of repeated courses. Also of great importance is the form of taking (tablets, ointment, injections, intravenous infusions). For example, a cross-allergy to penicillin with an injection or intravenous infusion can cause a more severe allergic crisis than tablets;

2. From the patient himself

This applies to allergic (atopic) history and hereditary allergies. Still it is necessary to know, that some illnesses aggravate occurrence of allergic reaction to some preparations. So for viral diseases like mononucleosis, amoxicillin (moxifen, ogmanthin) causes a skin rash, and when AIDS develops a hypersensitivity to sulfanilamide drugs.

Approximate allergic reaction to drugs

Penicillin

Penicillins are a broad group of antibiotics with a similar structure. The oldest penicillins used in medicine for a long time have a very similar mechanism of action (cross sensitivity). However, in other groups of penicillins, the identity of action (in particular cephalosporins) does not exceed 15%. If there is a severe cross-allergy to drugs or even anaphylactic shock, the presence of antibodies to penicillin can be checked with a special laboratory test. Provided that the patient had a severe allergic reaction in the past, but he needs a second dose of the drug to fight more resistant bacteria and nothing helps with antibiotics, then it is possible to reduce the sensitivity to penicillin by desensitization.

Aspirin and non-steroidal anti-inflammatory drugs

Similar drugs for allergies cause skin rashes, runny nose, shortness of breath, swelling and anaphylactic shock. People who suffer from chronic urticaria and asthma are more sensitive to such remedies. In patients who are hypersensitive to drugs from the group of nonsteroidal, almost certainly there will be an allergic reaction to any anti-inflammatory drugs. It is better for such people to refrain from taking them. There are safer new anti-inflammatory non-steroid drugs that belong to the group of selective inhibitors. Paracetamol and optalgin are not included in this group, and in most cases, their administration has no contraindications.

Cross-allergy to iodine

Many X-ray contrast preparations contain iodine, but under confirmed data iodine alone is not an allergen. The common opinion that it is not possible to use X-ray contrast preparations, if iodine causes a skin rash in the patient or if it has a cross-allergy to sea fish, is unfounded. Some people already feel a shortness of breath after a few minutes after the injection, they develop a rash, swelling of the larynx and shock.

The risk of developing allergies in people who have had it in the past can be reduced. But drug treatment should be started 12 hours before the introduction of the contrast drug intravenously during the X-ray examination. In any clinic, you can get an analysis of the response to medications, and also make a diagnostic or provocative test to justify your suspicions.

Allergy to anesthetics used in dentistry

There are cases when local anesthesia during dental treatment caused dizziness, weakness, loss of consciousness and increased heart rate in the patient. In most cases, this does not apply to allergic reactions, it's just the effects of fear or side effects of the drug. To test your suspicions of an allergy to anesthetics, you need to perform a diagnostic test. This will help prevent allergies during the next visit to the dentist.

How to recognize a cross-allergy to medicines?

The characteristic allergy to drugs develops very quickly - just a few minutes after getting into the body of the drug. The problem is that many patients take several drugs at once. That's why it's sometimes difficult to determine which medicine exactly causes allergies. This is important for the doctor to understand whether the reaction is indeed allergic. He needs full information about the nature of the reaction, about the existing allergies in the past - the entire history of the patient's illness.

It is difficult to identify the cause of cross-allergy with a skin test or a blood test, so when you first suspect an allergy it is recommended to consult an allergist. He must decide on the continuation of the drug. Sometimes a skin test is used using the allergen itself. Such a test is potentially dangerous and is conducted only in the hospital.