On first contact, the immune system can classify a potentially allergenic substance (allergen) as “dangerous” and memorize it. This mechanism is called sensitization. The next time you come into contact with the allergen in question, allergic reactions occur for the first time. These can become increasingly severe over time. If left untreated, an allergy can also lead to chronic symptoms such as bronchial asthma.
It is therefore advisable to prevent allergies as far as possible – ideally from an early age. This is because the predisposition to allergies is hereditary. This means that if a father or mother has an allergic disease (such as hay fever, asthma or neurodermatitis), the child has an increased risk of also becoming allergic. This risk is even higher if both parents are allergic to something – especially if it is also the same type of allergic disease (e.g. hay fever). Children who have siblings with an allergy also belong to the risk group (increased allergy risk).
Primary prevention
No nicotine
Active and passive smoking during pregnancy and breastfeeding as well as after birth increases the risk of a child developing allergies (especially asthma). Apart from this, tobacco smoke can also make you ill in other ways, for example by causing cancer.
So there are several reasons why a smoke-free environment is fundamentally important – especially for pregnant women, breastfeeding mothers and children.
Nutrition during pregnancy and breastfeeding
During this time, experts recommend a balanced, varied diet that meets a woman’s nutritional requirements. The diet should include vegetables, milk and dairy products (such as yogurt and cheese), fruit, nuts, eggs and fish.
It is not necessary for pregnant or breastfeeding women to avoid common allergy triggers in their diet (such as cow’s milk or peanuts) – this does not affect the child’s risk of allergies.
Healthy body weight
To prevent asthma in children, women should avoid being overweight or obese before and during pregnancy. A healthy body weight is also important for children and adolescents themselves: asthma is more common in overweight/obese children than in those of normal weight.
“Normal” delivery, if possible
Children born by caesarean section have a slightly increased risk of asthma compared to babies delivered normally (vaginally). Parents should bear this in mind when considering an elective caesarean section (i.e. a caesarean section that is not medically necessary).
Breastfeeding
Ideally, mothers should fully breastfeed their babies for the first four to six months. If they then gradually introduce complementary foods, they should continue to breastfeed their children for the time being.
You can read more about the duration of breastfeeding in the article “How long to breastfeed?”.
Infant formula
Babies who cannot be breastfed or cannot be breastfed sufficiently should be given infant formula.
In the first few days of life, however, industrially produced infant formula based on cow’s milk (cow’s milk-based formula) should not be fed if the mother wants to breastfeed (it can take a few days for milk to come into the breast). Instead, for temporary formula feeding in the first few days of life, mothers should choose a preparation in which the milk proteins are highly broken down (extensively hydrolyzed therapeutic formula) or which only contains protein building blocks (amino acid formula).
Other animal milks such as goat’s milk (also used as a basis for infant formula), sheep’s milk or mare’s milk have no allergy-preventing effect. The same applies to soy-based infant formulas (soy products can, however, be part of complementary foods – irrespective of the purpose of allergy prevention).
Complementary food and transition to family nutrition
Depending on your baby’s readiness, mothers should start introducing complementary foods from the beginning of the 5th month at the earliest and from the beginning of the 7th month at the latest.
Avoiding common food allergens (such as cow’s milk, strawberries) in the first year of life is of no benefit in terms of allergy prevention. Experts therefore advise against it. Instead, there is evidence that a varied diet in the first year of life can protect against atopic diseases such as hay fever or allergic asthma. A varied diet also includes fish, a limited amount of milk/natural yoghurt (up to 200 ml per day) and hen’s eggs:
To prevent a hen’s egg allergy, experts recommend thoroughly heated hen’s eggs, such as baked or hard-boiled eggs. Mothers should introduce them with complementary food and give them to their child regularly. However, “raw” hen’s eggs (including scrambled eggs!) are not recommended.
Recommended vaccinations
All children should therefore be vaccinated according to current recommendations (including children with an increased risk of allergies).
No excessive hygiene
Too much hygiene in childhood apparently promotes the development of allergies. According to the hygiene hypothesis, the child’s immune system needs microbes and dirt to mature. This is supported by the fact that children who grow up on a farm are less susceptible to allergic diseases.
Avoid mold and indoor air pollutants
Make sure that no mold grows indoors (especially in bedrooms). To do this, you should ventilate regularly so that the humidity in the rooms does not rise too high.
To prevent allergies, air pollutants in rooms should also be avoided as far as possible. In addition to tobacco smoke, this also includes pollutants that are released, for example, by outgassing from floor coverings or furniture.
Beware of car exhaust fumes
Nitrogen oxides and small particles from traffic emissions can increase the risk of asthma, among other things. Children (and adults) should therefore be exposed to such emissions as little as possible (e.g. avoid playing or living near busy roads if possible).
Secondary prevention
Secondary prevention is important for people with an increased risk of allergies who are not (yet) ill (e.g. babies of allergic parents). On the other hand, it is advisable if the immune system has already been sensitized – the first step towards an allergy.
Hydrolyzed infant formula
Hydrolyzed (hypoallergenic) infant formulas (HA formulas) are said to be particularly useful for children at risk for the prevention of an allergic disease – according to the advertising claims of many manufacturers. So far, however, such products cannot be generally recommended for allergy prevention.
One reason for this is that the available products differ considerably in various respects – for example, in the source of protein they contain and the extent to which the proteins are broken down during production.
Secondly, studies in which such hypoallergenic infant formulas were examined are very heterogeneous – for example with regard to the duration of the study, the group sizes or the influence of the industry.
Babies at risk of allergies should therefore check whether an infant formula is available that has been shown in studies to be effective in preventing allergies. This is recommended by the current guideline on allergy prevention.
The European guideline on the prevention of food allergies in babies and young children also contains no recommendation for the use of hydrolyzed infant formula – but also no recommendation against it. There is no clear evidence that these infant formulas can prevent food allergies in children. However, there is also no evidence that HA foods are harmful to children.
Parents of children at risk should seek advice on the subject of hypoallergenic infant formula, for example from their pediatrician.
Pets
Families or children with an increased risk of allergies should not get a new cat. However, there is no recommendation to get rid of an existing pet – there is no evidence that this would have an impact on the risk of allergies.
Tertiary prevention
Tertiary prevention of existing allergic diseases aims to prevent, limit or compensate for an exacerbation and possible consequences of the disease.
For example, patients with allergic asthma sometimes benefit from climate therapy (e.g. spa stays at the seaside, in the low and high mountains). Inpatient rehabilitation can also be useful.
In the case of allergic rhinitis (with or without allergic conjunctivitis), experts recommend specific immunotherapy to prevent the development of allergic asthma. The procedure is also known as hyposensitization:
A doctor administers gradually increasing doses of the allergen to those affected – either in the form of a solution or tablet under the tongue (sublingual immunotherapy, SLIT) or as an injection (syringe) under the skin (subcutaneous immunotherapy, SCIT). The aim is to gradually accustom the immune system to the allergy trigger so that it reacts less sensitively to it.
An allergic rhinitis (possibly with allergic conjunctivitis) is a symptom of pollen allergy (hay fever), animal hair allergy and house dust allergy, for example.
If you are allergic to house dust mites (house dust allergy), you should make sure that your home has as few mites and mite droppings as possible. This means, for example:
- Carpeted floors should be vacuumed several times a week, preferably using an appliance with a special fine dust filter.
- Smooth floors should be damp mopped once or twice a week.
Babies with atopic dermatitis whose family regularly consumes peanuts may benefit if peanut products are introduced in an age-appropriate form (such as peanut butter) with the complementary food and then given regularly. Peanuts are one of the foods that often trigger flare-ups or worsen the symptoms of atopic dermatitis. However, doctors should first rule out a peanut allergy, especially in babies with moderate to severe atopic dermatitis.
Tertiary allergy prevention for children with atopic dermatitis also includes the advice not to get a new cat.
