1. Biscuits, gingerbread, chocolate

Many holiday treats contain hazelnuts, which are among the most allergenic tree nuts in Central Europe. Children are especially prone to having a primary food allergy to hazelnuts, which often leads to severe skin, gastrointestinal or respiratory symptoms. If the allergy appears in adulthood, the symptoms are usually less pronounced. In this case, the trigger can be an allergy to birch, hazel or alder pollen. Sometimes the pollen allergy even remains undetected. If it develops into what is known as a cross allergy, many allergy sufferers experience a sudden reaction to hazelnuts in which their lips, tongue or gums start to tingle, go numb or swell.

• Tip: People with a cross allergy can sometimes tolerate roasted hazelnuts, but not raw hazelnuts. Patients are advised to seek individual assessment by an allergist.

If you do your own baking, you can control what goes into it. Here is a popular recipe for nut-free biscuits.

2. Spices

Christmas spices such as anise, coriander and cumin can cause problems in people with an allergy to mugwort pollen, a common trigger of hay fever in late summer. These spices contain allergens that are similar to mugwort and therefore need to be avoided by many people with this allergy. People who are allergic to celery at the same time are referred to as having ‘celery-mugwort-spice syndrome’. This can cause symptoms in the mouth or throat.

Cinnamon also has its risks, although from an allergological perspective it is safe to consume. However, prolonged skin contact with the oils in the cinnamon can sometimes trigger a contact allergy, resulting in a skin rash. This condition mostly affects bakers and confectioners. The oil contains cinnamaldehyde, a known allergy trigger. There are also (synthetic) perfumes in cosmetics, toothpaste and cleaning products that can provoke contact allergies on the skin and mucous membranes of people who are already sensitised.

3. Winter meals

Some of the foods traditionally served in winter, such as sauerkraut, fish products and smoked ham, are fermented, aged and preserved. Like red wine, they contain a lot of histamine, which can trigger an intolerance in certain people. This is commonly thought to be an allergy, but it is not, even if the symptoms include a runny or stuffy nose, gastrointestinal symptoms or hives. It is not clear what causes this intolerance, but it could be due to a lack or reduced activity of the enzyme that breaks down histamine. Other factors may also play a role, such as alcohol, medications, or gut bacteria.

• Recommendation: If histamine intolerance is suspected, consult an allergy specialist in order to rule out other diseases. A three-week low-histamine diet can help clarify the diagnosis. If the allergy is confirmed, a long-term diet might not be necessary – foods containing histamine should be eaten now and then to check whether a tolerance is developing.

4. Poinsettias

With its bright red leaves, this plant is a classic Christmas decoration, but it is unsuitable for people who are allergic to latex. This is because proteins in the poinsettia are similar in structure to latex proteins and can therefore trigger allergic rhinitis and/or conjunctivitis in people who are already sensitised. This can happen even without touching the leaves. Just being in the same room as the plant can trigger a reaction, because the plant allergens can also be spread through house dust.

• Alternative: Choose other decorations or hostess gifts. Helpful hint: People who are allergic to latex should also avoid plants such as Christ thorn, ficus, rubber fig, evergreen and oleander.

5. Cold temperatures

Cold temperatures and dry air from heaters can make allergies worse by putting even more stress on skin that is already dry from atopic dermatitis. Mild eczema and itching occur as the skin loses moisture. Cold temperatures can also be hard on allergy sufferers with mixed-type asthma. The cold air irritates their hypersensitive bronchia, making them more prone to asthma attacks. Finally, many people who are allergic to house dust mites notice that their symptoms worsen as soon as the heating season begins. Although the mites die under the dry conditions, the heating stirs up allergy-triggering mite particles and droppings, more of which are then inhaled.

Here are some tips for managing atopic dermatitis and house dust mite allergies.