What is a drug allergy?
If your body reacts sensitively to certain ingredients in medication, this may be a drug allergy. In 80 percent of cases, however, it is not an allergy but undesirable side effects. In the case of a drug allergy, your immune system reacts specifically to a medication.
If you develop an inflammatory skin rash as a result, we speak of drug exanthema. The rash can be limited to a specific area or cover your whole body. The symptoms often disappear of their own accord.
In principle, every active pharmaceutical ingredient has the potential to trigger a drug allergy or drug exanthema.
- It may be relevant how your metabolism processes a drug, whether it is distributed throughout your body, concentrated in a few cells or even in a specific part of it. A certain genetic predisposition can also prevent the desired processing.
- Last but not least, a substance can only become allergenic during processing in the organism.
- Practically all medications can trigger allergies. However, some have a higher potential. These include, for example, certain antibiotics, anesthetics and painkillers.
- Sometimes the immune reaction is not to the active substance itself, but to an excipient or additive in the medication, such as fillers, stabilizers, flavourings and colourings.
Drug allergy: causes and risk factors
Certain risk factors make the onset of some types of drug hypersensitivity more likely:
- They are female.
- They are between 20 and 49 years old. (If you are older, intolerances occur less frequently but can be more serious).
- You take a medication irregularly or suddenly increase the dose.
- You are currently suffering from a viral infection (e.g. B. herpes, HIV).
- Your immune system is disturbed.
- You have cancer.
- You suffer from mastocytosis (skin form or generalized form), which can increase the severity of an anaphylactic reaction to histamine-releasing drugs.
What kind of drug allergies are there?
Allergic reactions to medication can manifest themselves in different ways.
Immediate type reactions occur, as the name suggests, within a few minutes to hours after taking the medication. These anaphylactic reactions can be very dangerous and must be treated immediately. Manifestations of such reactions range from skin symptoms (e.g. hives) to gastrointestinal complaints (e.g. nausea and vomiting) and respiratory complaints (such as shortness of breath and hoarseness). The most severe form is anaphylactic shock (circulatory collapse).
Late type reactions occur later, usually within days to weeks/months after starting the medication. The most common is a red, sometimes very itchy skin rash (drug exanthema). This is harmless in the sense that it is limited to the skin and no other organs are affected. Severe late-type reactions are rare. They express themselves
- with extensive blistering of the skin and mucous membranes (Stevens-Johnson syndrome, toxic epidermal necrolysis)
- with facial swelling, rash, blood count changes and organ damage(Drug Reaction with Eosinophilia and Systemic symptoms)
- with pustules and redness on the skin (Acute generalized erythematous pustulosis)
Drug allergies: Diagnosis and treatment with us
If you notice possible symptoms of an allergy, contact your doctor. For all drug allergies, the triggering or suspected drug(s) must be stopped (except in exceptional cases).
Further treatment depends on the type of allergy. Depending on the severity, antihistamines, cortisone preparations and adrenaline injections are used for immediate type reactions. Cortisone preparations are used for late-type reactions, and biologics or infusions for severe reactions. Patients with severe reactions must be treated in hospital. A provisional allergy passport will record which medications or groups of medications you are no longer allowed to take/use until the allergy assessment has been completed.
How does the allergology assessment work?
If you have been diagnosed with or are suspected of having a drug allergy, you will need an allergy assessment. Clarification should take place at the earliest four to eight weeks after the reaction.
At specialized centers such as our allergy ward
The first step is to find out what symptoms you have had and what medication you have been taking. The more information we receive from your pre-treatment physicians, the better.
In the second step, tests are carried out which include skin tests and blood tests. In the skin tests, drug extracts are applied to the skin or introduced superficially. After about half an hour (prick test, intracutaneous test) or several days (epicutaneous test), the reaction is read on the skin.
The blood tests examine whether your immune cells react to the suspected drugs and/or whether you have antibodies against them (lymphocyte transformation test, basophil activation test, IgE measurements).
Depending on the results, several appointments / steps may be required. The main reason for this is that the test results are not always unambiguous.
In some cases, a “provocation test” is carried out. You will then receive an alternative preparation from us under close supervision. This is a medicine that could be used as an alternative to the one(s) you are allergic to.
At the end of the allergology assessment, we will discuss with you which medications you need to avoid and how to proceed in the event of a new reaction.
You will receive an allergy pass from us. This lists the type of reaction and the medications that you must avoid and, if applicable, which ones may be given. You should always carry your allergy passport with you and keep it with your
Drug allergy, drug exanthema: prevention, early detection, prognosis
You cannot prevent a drug allergy or drug exanthema, as your body can have an allergic reaction to all medications. There is also no specific possibility of early detection.
Prevent
- If we prescribe a new medication for you, please be sure to inform us if you have had an allergic reaction to drugs in the past.
- Get an allergy passport and always carry it with you. If you are unresponsive in an emergency situation, the passport can save your life.
- If you want to treat yourself with a non-prescription medicine from the pharmacy, talk to the pharmacist about your drug allergy.
- If you have reacted to preservatives in a medicine with allergic symptoms, you should try to use only medicines without these additives.