Wir überwinden Grenzen

(27.04.2016) Michael Huber* actually feels healthy. But from time to time he is seized by an inner restlessness, develops rashes, reddening of the skin and shortness of breath. Twice he even feels dizzy and collapses unconscious. The patient suspected an allergy to food additives and contacted the outpatient clinic of the Department of Dermatology and Venereology at the Freiburg University Medical Center. However, the corresponding tests remain negative. "The reactions only occurred a few hours after a meal. This is actually unusual for an allergic reaction," says Dr. Sabine Müller, senior physician at the Department of Dermatology and Venereology and acting head of the allergy outpatient clinic.

Nevertheless, the doctors continue to investigate the suspicion. The patient subsequently keeps a food diary. He even notes down his prescriptions in detail. This revealed that he had mostly eaten meat or sausage products, often in combination with alcohol or physical exertion, before he felt unwell. "In some cases, allergic reactions only occur when allergens and stressful situations interact," says Dr. Müller. The doctors use the recipes to test all the ingredients individually. However, meat allergies have not yet been proven with certainty at this stage and the usual allergy tests using a meat solution remain negative.

However, reports of allergic reactions to red meat, for example from pigs and cattle, have also been increasing in the south of the USA over the last 10 years. However, the researchers only got on the right track when a group of cancer patients reacted allergically to a new drug at the same time. After a long search, they discovered that only people who had previously been bitten by a tick were affected. When ticks bite, they transfer part of their saliva and thus also a sugar called alpha-galactosidase. This sugar is found in the cancer drug and on mammalian meat. A blood test is being developed that detects antibodies against the sugar. "The new test came at just the right time for our patient. It enabled us to clearly diagnose him with a meat allergy," says the doctor. The fact that Michael Huber can't remember a tick bite doesn't mean anything. "Tick bites often go unnoticed if they don't cause any reddening of the skin," says Dr. Müller.

But Michael Huber is not yet convinced. He loves eating meat and doesn't want to give it up. The doctors suggest a provocation test. Under supervision, he eats a specially prepared piece of beef and then rides a bicycle ergometer - without any reaction. Even after eating pork and exercising at the same time, nothing happened. In a third test, he eats roasted pork kidney. This is because offal is particularly rich in the suspected sugar. In fact, the patient collapses shortly after eating it. The doctors present immediately inject him with antihistamines, cortisone and adrenaline to combat the allergic shock.

After this test, the patient no longer finds it difficult to change his diet. "The good news for patients with meat allergies is that they can eat poultry and fish without hesitation. The bad news is that you can't be desensitized at the moment," says Dr Müller. In addition to meat, sufferers must also avoid gelatine and some medicines that contain sugar. Detailed consultation with the treating doctor is therefore very important. In Michael Huber's case, the doctors' recommendation is having an effect. Since making the consistent change, he has been seizure-free - and his enjoyment of food has also returned.

* Name changed by the editors