Medication allergies can be very problematic because when the immune system classifies an active ingredient as hostile, the healing process of an illness or injury can sometimes be severely impaired. True drug allergies are rare, but there are many medications, and any active ingredient can potentially trigger an allergy.
That is why around one quarter of the population in this country develops a medication allergy at least once in their lifetime. Diagnosing it can be difficult because the symptoms often resemble drug intolerances or side effects, which are much more common. Fortunately, life-threatening consequences of drug allergies are also rare.
What is a medication allergy?
A medication allergy is an immune system defense reaction to a specific medication or active ingredient. The allergy can remain undetected for a long time if it resembles possible side effects of the respective medication.
However, in a large proportion of suspected cases, the issue is not an allergy but an intolerance to a medication. While intolerances are usually associated with metabolic problems, in drug allergies antibodies are produced that attack the presumed harmful substance.
A medication allergy can occur as an immediate or delayed reaction. An immediate reaction appears shortly after taking the medication - either after just a few minutes or after several hours.
The symptoms range from respiratory problems to nausea, vomiting, or diarrhea. Skin redness, as well as wheals and hives, can also occur. The short-term symptoms of a drug allergy can be very severe. Nevertheless, life-threatening anaphylactic shock is rather rare.
Delayed medication allergies often do not appear until several days after use. This can make diagnosis much more difficult. However, there are some symptoms that occur relatively frequently in connection with allergies to medications. A drug rash is typical of medication allergies, for example.
This is a reddened skin rash that can spread across large areas of skin or the entire body. A drug rash is bothersome and can appear frightening, but is itself harmless. Severe consequences are rare with delayed reactions, but they do occur. Stevens-Johnson syndrome, for example, is characterized by blistering of the mucous membranes and other areas of skin.
The most common medication allergies occur in connection with the following drugs:
Antibiotics, with penicillin usually being the trigger.
Painkillers such as ibuprofen or ASA. In the case of ASA, however, it is usually an intolerance - ASA intolerance syndrome - that occurs as an accompanying symptom of allergies.
Rheumatism medication - more precisely, anti-inflammatory drugs such as nonsteroidal anti-inflammatory drugs (NSAIDs).
Antidepressants and neuroleptics
Anesthetics and anesthetic agents
Blood pressure medications such as ACE inhibitors
Medications for epilepsy
Medications for chemotherapy
Contrast agents for X-rays
How is a drug allergy diagnosed?
The diagnosis of a drug allergy does not differ significantly from other allergy tests. However, it must first be determined which medication should be tested or whether the symptoms could have other causes.
Many of the symptoms can also occur with other illnesses and allergies, food intolerances, or food poisoning. Your doctor will therefore begin with a detailed medical history. Among other things, they will ask when and how often the symptoms occurred and which medications were taken.
The dosage of the medications can also play a role. For people who take many different preparations, it may therefore take some time to find the trigger of a medication allergy.
Once the most likely triggers have been identified, various allergy tests can be performed. To diagnose immediate reactions, the skin prick test is often used, for example.
Liquid drops containing dissolved active ingredients are applied to previously marked areas of skin. A needle is used to prick the skin through the drops, allowing the active ingredient to penetrate. If an allergy is present, skin reactions should appear within the next few minutes.
For substances whose effects only appear after a longer period, the patch test is preferred. Patches containing possible allergens are applied to the skin for one to two days. Once the time has elapsed, the skin is checked for reactions that could indicate a drug allergy.
Blood tests can also be performed as a supplementary measure. Another diagnostic option is the provocation test, in which a small amount of the suspected allergen is taken under medical supervision. Only the treating specialists can decide which type of allergy test is appropriate.
How are medication allergies treated?
Medication allergies cannot be alleviated through desensitization. The only way to prevent symptoms is to completely avoid the trigger. The medication in question can therefore no longer be taken. Fortunately, for most medications, alternatives with different active ingredients and comparable efficacy are available.
If a medication that is urgently needed cannot be replaced with an equivalent alternative - for example, during cancer treatment - continuing to use it despite the allergy may be considered. The effects of the drug allergy must then be weighed against the benefits of the medication.
Acute symptoms can be treated with antihistamines or cortisone. Adrenaline is also used in the event of anaphylactic shock. Special emergency kits are available for allergy sufferers with life-threatening drug allergies.
These kits contain emergency medications such as epinephrine, which can be self-injected using a pen-like applicator.
If you suspect that you are allergic to a medication, you should definitely seek medical help. With a medication allergy, it may take some time before a clear diagnosis is established. It is therefore better to visit an allergy clinic or practice sooner rather than later.
