Introduction
Drug intolerance is an immune reaction of the body to locally applied or otherwise taken drugs. It is therefore ultimately a kind of allergy. Like other allergic reactions, it is an excessive reaction of the immune system to harmless substances (allergens).
This defensive reaction then manifests itself in inflammatory processes, which can take on the most varied manifestations. In principle, all drugs can trigger drug intolerance. However, allergic reactions are observed particularly frequently with certain drugs.
This is partly due to their chemical composition, but also to the fact that these drugs are prescribed and taken more frequently than others. Typical triggers of an immune reaction are also gold preparations, which are still used in the treatment of rheumatic diseases. In addition to these synthetically produced preparations, herbal medicines (phytotherapeutics) and even vitamin preparations can cause intolerances.
Typical for allergies in general are so-called cross-allergies. Here, a chemically related substance can also trigger an allergy if another substance is incompatible. A classic example of this is the intolerance of apples in the case of an existing birch pollen allergy; both contain a very similar protein. In relation to medication, a frequently occurring cross-allergy is that of penicillins and cephalosporins (both antibiotics).
- Antibiotics
- Antiepileptic drugs
- X-ray contrast medium
- Painkillers (analgesics)
Symptoms
Drug intolerances can cause a whole range of symptoms, but most of them are quite harmless. The most common are skin rashes, itching, blistering and hives (urticaria). Severe allergic reactions can present themselves as allergic asthma.
In this case, the histamine released by immune cells triggers swelling of the bronchial tubes and thus breathing difficulties. In the worst case, anaphylactic shock can occur, the maximum reaction of an allergic reaction. This can be fatal without immediate therapy.
At the beginning, symptoms such as itching, burning and a feeling of heat in the throat and the finger and toe tips occur briefly. Almost parallel to this, swallowing difficulties and a bronchospasm occur, which can lead to respiratory distress. The resulting lack of oxygen in the body is reflected in a blue coloration of the lips (cyanosis).
As a result, there is a circulatory shock with a drop in blood pressure and palpitations (tachycardia). If symptoms such as severe itching, asthma and swelling of the lips or face are observed after taking medication, an emergency doctor must be called immediately. Skin rash (exanthema), more precisely a drug exanthema is the external appearance of a drug intolerance and is the most common manifestation of this.
When a drug is taken for the first time, skin rash usually occurs between the 7th and 12th day of treatment. If the drug has been taken before, sensitization has already taken place and drug exanthema now occurs within the next 48 hours. In addition to a real allergic reaction, however, it can also be a so-called pseudoallergy, which without sensitization can trigger a skin rash even after the first intake of the drug.
The appearance of a drug exanthema can vary. Scarlet redness can occur as well as a rash similar to measles or small round or oval nodules (papules). The formation of large red spots, so-called erythema, is rather rare. A characteristic feature of all drug-induced rashes is that they usually occur in different, but individually always the same parts of the body. Once the rash has healed, a grayish pigmented skin usually remains for the next time.
All articles in this series:
