Atopic dermatitis and allergic asthma

With the help of timely prevention, atopic dermatitis in children can be prevented. This is shown by at least two clinical studies – PREVENTIA and ETAC, the results of which were recently published. They suggest that the use of antihistamines such as loratadine can prevent or at least reduce the spread of atopic dermatitis and its transformation into allergic rhinitis and allergic asthma. This was the subject of an interview with prof. Dr. Enno Christophers (Keel) at the 9th Respiratory 2000 in New York.

The high risk group for atopic dermatitis includes young children who not only suffer from atopic eczema, but are also sensitized to pollen or perennial allergens. It is believed that 50-60% of them may later develop asthma. In your opinion, what are the chances for a dermatologist to prevent or at least reduce the possibility of asthma in the future with timely prophylaxis with an appropriate antihistamine?

Prof. Christophers:

In principle, from the point of view of pathophysiology, what happens on the skin of a person occurs both in the bronchial epithelium, and in the lungs, and generally in the entire bronchial system. This means that the mechanisms of inflammation with the release of very active mediators act on the skin as well as on the bronchial epithelium. This is due to the fact that a well-developed protective system works here, which causes both skin and bronchi in both organs, diseases and dysregulation.

Can we say that the factors causing the disease are identical or are there differences? For example, with atopic eczema, other parameters are involved in comparison with allergic rhinitis or allergic asthma?

Prof. Christophers:

It is very difficult to answer this question. At least when you are dealing with the bronchial system, you can quite accurately say when there is an allergic disease. We can identify it, prove it, and explain the mechanism that triggers the seizure. Atopic eczema is a special case. Often we simply do not know which allergen is causing it, we cannot determine it, but still it is, since there is atopic eczema. Therefore, it is very difficult to interpret and explain the connection here.

In addition, atopic eczema is a special situation. It is quite possible that we took different diseases or different forms of the disease, kind of mixed them up and called them atopic eczema. Yet the mechanisms that lead to the development of atopic eczema are identical to those that cause allergic asthma in the lungs. Therefore, with both diseases, the same principle applies: both on the skin and in the bronchial system, treatment should be started as early as possible. The main task is to prevent the “rocking” of the pathophysiological mechanism of the disease and to ensure its stabilization. After all, the so-called “hyperallergic lung” or hypersensitive bronchial system is the result of prolonged irritation and prolonged exposure to antigens.

And can these mechanisms be suppressed, for example, by administering an antihistamine?

Prof. Christophers:

Atopic eczema has a pronounced tendency to relapse, and therefore it is recommended to treat both children and adults for quite a long time, with antihistamines specially designed for this indication. These include, in particular, loratadine. In recent years, we have learned to better understand the mechanisms of action of drugs. So, earlier we assumed that one of the mechanisms of action of the drug is blocking the release of histamine. However, it is now clear that antihistamines have multiple effects. These include a clear anti-inflammatory effect, i.e. the release of mediators is blocked. Receptors no longer express, and thus it is possible to influence the complex mechanism of inflammation, as it were, from different angles. Obviously, this explains the encouraging results of large multicenter clinical trials. They confirm the effectiveness of the antihistamine loratadine with prolonged use to prevent the development of symptoms of atopic dermatitis.

event_note July 14, 2020

account_box Winona Tse MD

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