Is prophylaxis possible?

Prophylactic skin care from birth appears to be the most effective prophylactic measure for atopic eczema in at-risk infants. Breastfeeding, even if not exclusively, in the first 4-6 months has a moderate, prophylactic effect in high-risk infants. The introduction of complementary feeding should be analogous to skin-healthy children. Provided that no appropriately sensitized persons live in the household, it is not necessary to advise against keeping a furry animal.

The prevalence of atopic dermatitis remains persistently high worldwide. This fact calls for prevention strategies, since eczema has a chronic course with usually high suffering of the affected persons. Parents with atopy often receive tons of well-intentioned advice. But what can we recommend to them based on evidence?

Breastfeeding – really as effective as assumed?

Breastfeeding for four to six months is commonly regarded by society as one of the most important measures for the prophylaxis of atopic eczema. But is this recommendation also supported by science?

Certainly, breastfeeding is clearly preferable to bottle milk for nutritional, immunological, and psychosocial reasons. However, its effect in terms of eczema prevention is not quite so clear. In general, however, recent data appear to attribute a moderate beneficial effect to breastfeeding, with only high-risk infants appearing to benefit with respect to eczema [1,2]. Probably wrong is the view that breastfeeding must be exclusive – so high-risk infants who are fed benefit equally from the protective effect of breastfeeding [2].

If breastfeeding is not possible, it was previously recommended to use (partially) hydrolyzed infant milk until the age of six months. However, recent meta-analyses conclude that the evidence for this recommendation is not convincing [3]. The Nutrition Commission of the Swiss Society of Pediatrics now takes these findings into account and no longer supports the use of (partially) hydrolyzed infant formula [4].

Is it necessary to avoid certain foods during pregnancy and breastfeeding?

In general, special diets, especially avoidance of potential food allergens during pregnancy and lactation, are not recommended in the absence of evidence regarding eczema prevention. Overall, a balanced diet should be aimed for. A Mediterranean diet and the consumption of vegetables and fruits as well as fish seem to have a positive effect with regard to eczema and allergy prophylaxis [5].

Introduction of complementary feeding for eczema children – when and how?

The previously valid recommendation to delay the introduction of potentially allergenic foods such as hen’s egg, fish and soy in eczema children has been abandoned for some time. Currently, the same recommendations apply to eczema infants as to all other children without atopy, i.e., a rapid and varied cosmesis from the completed 4th month of life [4].

Regular fish consumption can be recommended, as it probably has some preventive effect on atopic diseases [6].

Pro- and prebiotics

Increasingly, the role of the microbiome in the pathogenesis of atopic eczema is being recognized [7]. For example, the type of birth (sectio vs. vaginal) and the early use of antibiotics appear to influence the development of atopic eczema. Accordingly, the idea of counteracting eczema development by supplying “good” bacteria seems attractive. Indeed, some data exist with encouraging results in this regard, although negative results have also been published [8,9]. Unfortunately, the individual studies differ greatly in the bacterial strains or preparations used, the duration and timing of intake, so that no general recommendation can currently be made for the prophylactic intake of probiotics with regard to eczema development [4].

With regard to prebiotics, i.e. specific indigestible dietary fibers that promote the selective growth of microorganisms, there are also only a few studies with heterogeneous results, so that no recommendations exist for this at the current time either.

Is a pet bad for my baby?

This question not infrequently occupies families with children at risk of eczema. In the past, the general recommendation was to avoid furry animals if possible if there was a risk of atopy. However, the current literature paints a different picture. It shows that keeping a dog or other furry animals tends to be protective with respect to eczema, while no relevant effect (not even a negative one) results for cats [10]. Also regarding other atopical diseases no negative influence results from fur animal husbandry [11]. Although the data are somewhat too inconsistent to recommend general furry pet keeping in atopic families, it need not be discouraged, at least in the absence of appropriately sensitized family members, although dogs should probably be given preference over cats.

In principle, these findings support the “hygiene hypothesis” that early exposure to diverse microbial pathogens has a preventive effect. This is also shown by the fact that care in a nursery reduces the risk of atopy.

A reduction of house dust mite exposure by encasing measures (mite-allergen-proof covers) can currently also not be recommended as primary prevention, but probably in secondary or secondary prevention. Tertiary prevention.

Is tobacco smoke bad for eczema?

While it is very well established that secondhand smoke exposure is an important risk factor for early childhood asthma, the association regarding eczema is less well established. A recent metanalysis was able to show that the prevalence of eczema is higher with active and passive smoke exposure, both in children and in adults [12]. However, tobacco use during pregnancy does not appear to be a significant risk factor for later eczema development. Whether the relationship between eczema prevalence and tobacco use is truly causal requires further investigation. Nevertheless, tobacco use must be clearly discouraged in atopic families.

“Vaccinations are to blame for everything!”

It is well established that vaccinations are not associated with an increased risk of eczema [13]. Accordingly, children at risk of atopy should be vaccinated at the normal rate and completely. For eczema children, it is recommended to vaccinate against varicella in parallel with the measles-mumps-rubella vaccination.

Skin barrier

Over the past decade, a reduction in epidermal barrier function has been shown to play a central role in the pathogenesis of atopic eczema. Thus, eczema infants often exhibit primary reductions in key barrier components, such as filaggrin, claudins, and lipids. In addition, inflammatory cytokines secondarily lead to downregulation of the aforementioned components, further impairing barrier function [14]. The fact that the barrier defect is to be understood as a “primum movens” is underlined by the fact that the transepidermal water loss (TEWL) in the first days of life can be used to read off the risk for later eczema development [15].

This suggests that a prophylactic influence on later eczema development should be possible by supporting the skin barrier from birth. In fact, two independent controlled randomized pilot studies were published in 2014 suggesting this conclusion [16,17]. In both studies on a good 100 eczema-risk children, the daily application of a moisturizing cream reduced the risk of later eczema development by 50%. Another work confirms that this type of prevention is effective and also cost-effective [18].

These are promising results, but they need to be confirmed in larger studies over a longer period of time before official recommendations can be made. The onset, duration, which formulation and the impact on the microbiome should still be the subject of further studies.

Take-Home Messages

Prophylactic skin care from birth appears to be the most effective prophylactic measure for atopic eczema in at-risk infants to date.
Breastfeeding for the first four to six months has a moderate, prophylactic effect in high-risk infants regarding eczema. This remains present even if breastfeeding is not exclusive.
The introduction of complementary feeding for eczema children is analogous to that for skin-healthy children.
Provided that no appropriately sensitized persons live in the household, it is not necessary to advise against keeping a furry animal.

Literature:

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Osborn DA, Sinn JK, Jones LJ: Infant formulas containing hydrolysed protein for prevention of allergic disease and food allergy. Cochrane Database Syst Rev 2017; 3: CD003664.
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