Drug allergy: thousands of tests each year

Medications can – precisely dosed and concentrated – help people heal, relieve pain and save lives. However, sometimes the body may misinterpret this intention and suspect that there is a harmful intruder behind it and need to be fought.

Thorough tests

Drug intolerance can manifest itself in various forms, one of which is allergy. This is accompanied by a number of common symptoms, especially on the skin. However, definitive proof of an allergy to a specific active substance can only be provided by a complex test of several days in hospital.

Every year, more than 1,000 such drug allergy tests are carried out at the “Dermatology and Venereology” ward at the State Hospital in Feldkirch. About 5,500 patients from state hospitals and doctors’ offices are referred to Feldkirch each year for an explanation of suspected drug allergy. This year, the department celebrates the 20th anniversary of clinical dermatology and venereology in Vorarlberg.

Anyone can develop an allergy at any time

In the event of allergies, the human immune system always reacts in the same way: the body develops measures to combat it thanks to a specific recognizing substance. By itself, a completely normal defense reaction by which the immune system also fights off hostile pathogens, and which is essentially meant to protect against some 200 billion substances in the body.

“However, in the case of allergies, the reaction is wrong, the fighting structures mistakenly perceive a harmless substance as dangerous and take action against it. It is still unclear why this misdirection occurs. In fact, anyone – from young children to the elderly – can develop an active substance allergy at any time, ”explains Robert Strohal, head of the” Dermatology and Venereology “department at LKH Feldkirch.

Robert Strohal

State hospitals in Vorarlberg

Primary School Robert Strohal

Almost imperceptible to life-threatening

Common reactions in drug allergy vary in intensity and are unpredictable from person to person. They cover the spectrum from “barely noticeable” to “acutely life-threatening”. Drugs that only cause an allergy in one person after a week can cause anaphylactic shock in another person right after taking it: “It happens very suddenly and you always have to hurry. Although this reaction is rare, it can be fatal without medical attention, warns Strohal.

In addition, drug allergy usually manifests itself in various forms of rashes and skin lesions. Skin rashes can also become serious: according to Primar Strohal, it becomes especially dangerous when the rash affects large parts of the skin. About 250 patients are treated annually in Feldkirch for extensive skin infestation. This includes cases of skin peeling. Each year, an average of five affected people lose a large part of their skin.

Evidence of drug allergy

As a patient guidance, if rash affects more than ten times the size of the hand, they should be hospitalized urgently. Other symptoms of drug allergy include increased heart rate, dizziness, loss of consciousness, swelling in the hands and soles, lips, and face, and – and here it becomes life-threatening – swollen tongue that can lead to acute shortness of breath. In this case, notify the emergency services immediately.

Often there are drug allergies to certain antibiotics (e.g. penicillins), painkillers and rheumatics (acetylsalicylic acid, ibuprofen), X-ray contrast agents and heparin-like drugs, explains the head of the hospital pharmacy at LKH Feldkirch. Doctors and pharmacists are legally required to report any allergic reactions that occur as part of drug therapy to the authorities. In the event of a build-up of such reports, the authority may then arrange for the information to be tailored for healthcare professionals to the relevant medicinal product.

Gunther Graninger

State hospitals in Vorarlberg

Pharmacist Gunther Graninger

Testing takes several days

Depending on its severity, drug allergy is treated primarily with antihistamines and antiallergic infusions, as well as individually dosed cortisone. In addition, carefully coordinated ointment therapies are prescribed. Extremely complex and time-consuming tests are carried out in close cooperation with a specialist hospital pharmacy team in order to finally clarify a drug allergy.

Patients undergo a series of blood counts, skin and splash tests, along with meticulous monitoring protocols. Sometimes what is known as a “provocation” is necessary from a suspicious, extremely diluted active ingredient with a slowly increasing dose. The entire procedure takes several days.

Time-consuming and personnel preparation

Even the formulation itself is very time consuming and laborious: “As the active ingredients are scratched directly under the skin or injected into the skin, the formulation and dosing must be carried out under conditions that prevent bacterial contamination,” explains Graninger. A single production takes about an hour and a half and requires the involvement of two employees.

Overall, the LKH Feldkirch team is setting up tests for six different substances in the area of ​​painkillers, including well-known active ingredients such as acetylsalicylic acid, diclofenac, ibuprofen and paracetamol. In addition, the pharmaceutical industry has also developed ready-made test kits, which are also issued to the ward via the hospital pharmacy.

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