What is a nut allergy?

With a nut allergy , the body is allergic to nuts . People often experience tingling and itching in the mouth after eating nuts. In the event of a severe allergic reaction (anaphylactic shock), the affected person has circulatory problems and shortness of breath. It can be life threatening.

Nut allergies have increased over the past few decades. Doctors estimate that one to two percent of Europeans are affected. Which nuts a person is allergic to varies from person to person. The peanut allergy is the most common in Germany. From a botanical point of view, peanuts do not belong to the nuts, but to the legumes, but nutritionists often consider them to be nut allergies.

Hazelnuts and walnuts are other types of nuts that people in Germany are often allergic to. Some people cannot tolerate macadamia nuts either. Nuts such as almonds, cashews, pecans, Brazil nuts and pistachios can also trigger a nut allergy. The nutmeg is similar to the nuts, but it belongs to the seed plants and usually does not trigger any allergic reactions.

Doctors differentiate between two types of nut allergies :

• Primary nut allergy: This form already occurs in childhood and is often triggered by peanuts. The cause: the body mistakenly perceives certain proteins in nuts as enemies and reacts with symptoms. Doctors call these actually harmless proteins allergens.
• Secondary nut allergy: Doctors also refer to this form as cross allergy , it mostly occurs in adults. Doctors speak of a cross-reaction when a person first reacts to a certain allergen and then to another allergen that is similar to the first. People who are allergic to early-blooming pollen such as birch, alder and hazel often develop a nut allergy later on. This type of allergy often affects hazelnuts.

Most people are only allergic to one type of nut. Since the allergens in different nuts are similar, cross-reactions can also occur here. For example, a person with a hazelnut allergy can also be sensitive to almonds.

A peanut allergy persists for a lifetime in eight out of ten people . With other nut allergies, the chance is even lower that it will heal spontaneously.

Nut allergy: symptoms

An allergic reaction to nuts can trigger a variety of symptoms. The secondary nut allergy usually causes lighter symptoms:

• Often there is a so-called oral allergy syndrome . Those affected feel tingling, swelling, numbness or itching in the face or mouth - for example on the lips, on the tongue or on the mucous membranes.
• Others get a rash .
• In rare cases, people experience abdominal pain and indigestion.

With a primary nut allergy , people often have more severe symptoms:

• You may feel sick, vomit, or have diarrhea .
• The likelihood of an anaphylactic shock , i.e. a severe allergic reaction, is greater with this type. The risk is particularly higher with peanuts and hazelnuts. The bronchi constrict and cause symptoms such as coughing and shortness of breath. Blood pressure falls and the heart beats irregularly. In extreme cases, a nut allergy leads to cardiovascular or respiratory arrest. If you see a person in anaphylactic shock, you must call the ambulance immediately and give them emergency medication, if any!

Doctors classify the described signs of nut allergy into four degrees of severity :

• Grade I: changes in the skin (such as swelling, itching, and rash)
• Grade II: nausea and vomiting, runny nose, hoarseness and shortness of breath, high pulse, low blood pressure and cardiac arrhythmias
• Grade III: diarrhea and flatulence , swelling of the larynx, breathing cramps, blue-colored skin, shock of the cardiovascular system (circulatory failure, unconsciousness)
• Grade IV: respiratory and circulatory arrest

When it comes to anaphylactic shock is controversial among medical professionals. Some speak of it from grade II, others only from grade III.

When the symptoms of a nut allergy start and how long they last varies from person to person . Some people have symptoms immediately after eating the nuts in question. In others, the allergic reaction is delayed after a few minutes or hours. Symptoms can go away in a few minutes or last for several hours.

The amount at which the allergic reaction begins is also very different in the case of a nut allergy. Some people already get symptoms when they touch the nut or inhale its particles. Others can easily eat a handful before discomfort develops.

 

Nut allergy: test

Sufferers often wonder which doctor to go to. The pediatrician or family doctor , but also an ENT or dermatologist, is the right contact for a nut allergy. He will first ask you about your symptoms and eating habits. To diagnose a nut allergy, the doctor will usually order a series of tests. In a so-called prick test or skin test , he applies the allergens from nuts in the form of droplets to your upper arm. If the skin turns red or wheals form, this is a sign of a nut allergy.

During a blood test, the doctor will check whether you have certain antibodies to nut allergens. However, both a positive skin test and a positive blood test can only provide indications of a nut allergy. For example, every tenth school child in Germany has antibodies against peanut allergens. However, only a few of them are allergic to peanuts.

In the case of peanut and hazelnut allergies, so-called molecular diagnostics can provide further information. Here the doctor does not test the antibodies against complete allergens, but against components of them. If the test is positive for a certain component, it means that the patient has only mild allergic reactions - such as tingling or swelling of the skin. Other building blocks indicate an increased risk of severe allergic reactions - for example shortness of breath.

The provocation test is  the most reliable method for making a final diagnosis of a nut allergy and for reliably determining the severity of the allergy  . The doctor gives the patient various amounts of the suspicious nuts and observes whether allergic reactions occur. A provocation test may only be carried out under strict medical supervision - for example, by an  allergy specialist (allergologist)  in a clinic.

There are also many vendors on the internet who sell a nut allergy test. However, medical professionals warn against getting tested outside of the doctor's office. The offers are often dubious and very expensive.