Atopic Dermatitis in Children and Adults

Author: Sylvia Marinova, PhD student in the Genomic Stability Laboratory at BAS

Atopic dermatitis causes the appearance of red and itchy spots on the skin. The disease is the most common form of eczema and is more commonly known as atopic eczema.

Its onset is usually in early childhood, but it can occur at any age. Although its etiology is not fully understood, there seems to be a complex relationship between impaired barrier function of the skin, dysfunction of the immune system, infectious factors and those of the environment. The disease is also associated with food allergies, asthma and allergic rhinitis.

In this article you will read what science thinks about the root causes of atopic dermatitis, what are its triggers and what is the connection with other diseases. You will also learn how to take proper care of the good condition of the skin and prevent exacerbations of its condition in you or your child.

Atopic dermatitis is observed in 10% to 30% of children and in 1% to 3% of adults in developed countries [ref.1] and in recent decades there has been a significant increase in the spread of the disease. It is more common in areas with a high latitude. Perhaps this is due to the fact that the humidity is low and access to sunlight is more limited than in areas closer to the equator.

Atopic eczema usually occurs in early childhood . Up to 60% of cases begin in children even before their first birthday. Often the diseaseis "growing" by the age of 12, but in other cases it remains chronic and has its exacerbations in the later stages of life.

An initial occurrence of atopic dermatitis is also possible in adulthood after puberty. Another unusual form of the disease is the so-called senenium dermatitis - dermatitis, which occurs for the first time in adult individuals over 60 years of age.

Symptoms of atopic dermatitis are individual and vary from person to person. As a rule, it is characterized by the appearance of skin redness, which usually cause severe itching. Since the disease is chronic, alternation of periods of exacerbation of the condition with those of remission (complete recovery) throughout life or part of it is observed.

Other symptoms include:

• Dry skin - due to a lack of good hydration due to the impaired functions of the skin,
• Itching - can be very strong especially at night,
• Disturbed sleep - due to itching,
• Cracked and coarse skin,
• Sometimes inflamed skin maybe secreted or peeled

It is important to note that the impaired protective function of the skin makes it more prone to secondary infections with fungi, viruses or bacteria.

There is a difference [ref.2] between the place of occurrence of atopic zones in children andadults.

The etiology of atopic dermatitis is not yet fully understood.

• Role of genetics - it is known that the protein filagrin (more on what proteins are found here [ref.4]) is involved in the formationof the outermost layer of the skin, called the stratumcorneum.

Homozygous mutations in the filamine gene (this means that both copies of the gene are damaged) are associated with the early onset of atopic dermatitis and the development of more serious symptoms. Heterozygous mutations result in disorders in 50% of the protein produced. About 10% of Europeans [ref.6]heterozygous carriers of this defect.

The aforementioned mutation in filagarine cannot give a complete genetic justification for the occurrence of atopic dermatitis. It is known that differences in genes involved in immune system pathways are also a predisposing factor. Recent studies also indicate epigenetic changes (these are changes affecting which gene and when it will manifest itself) that play a role in the development of the disease. These changes are also due to interaction with environmental factors.

• Disregulation of the immune system - impaired regulation of certain components of the immune system is observed, as a consequence of which is the increased secretion of specific interleukins such as IL4, IL13, IL31, IL33. This leads to a violation of the barrier function of the stratum corneum of the skin, allergic inflammatory processes and suppression of the secretion of antimicrobial peptides.

• Neuroimmunological mechanisms - TSLP, as well as the aforementioned interleukins, lead to activation of signaling pathways that cause characteristic itching in patients. There is also a group of sensory neurons in the skin that produce histamine, which is again associated with inflammation and itching.

• Dysfunction of the epidermis - it is the result of impaired regulation of the gene expression of proteins, Interestingly, the malfunctioning of the epidermis not only leads to the development of atopic dermatitis, but also increases the risk [ref.7] of developing other allergies (such as food allergies) and leads to hyperactivity of the respiratory tract.

• Different lipid composition of the epidermis - different lipids have an important role in maintaining the barrier function of the stratum corneum. In patients with atopic eczema, their composition is different.

• Disorders in the microbiome - last but not least, we will mention changes in the microbiome of patients with atopic dermatitis. As we know [ref.8] the microbiome is the coexistence of multiple microorganisms in different organs of our body. in our body as much as cells.
  

The skin of patients with atopic dermatitis is characterized by pronounced dysbiosis especially during acute conditions. Some bacteria develop over-the-counter at the expense of others, disrupting the overall fine balance anddiversity.

In other words - it is very important to maintain the good condition of the skin and intestines with the right care and lifestyle, but on this we will pay more detailed attention below.

Atopic skin can be affected by some additional factors, since it isespecially sensitive:

• Stress - research suggests a link [ref.10] between atopic eczema and stress.
• Asthma or allergies (food or hay fever);
• Materials of clothing - examples are wool and nylon. Exacerbation can cause including some dyes in clothes;
• Cleaning products and cosmetics;
• Too hot or warm weather - large and sharp temperature amplitudes too;
• Cigarette smoke

Laboratory tests are not needed to diagnose atopic dermatitis . The treating dermatologist will examine you or your child and, based on a clinical picture and family history, will be able to assess whether thisdiagnosis is involved. At least three of the four main clinical findings in atopic dermatitis are needed:

• pruritus (itching),
• chronic or intermittent dermatitis,
• family encumbrivity,
• typical lesion location (described above)

The treatment of atopic skin is aimed at relieving symptoms. Depending on the severity of thedisease, there are various medications that your treating dermatologist can refer to. Here are a few tips foryour own skin care:

• Avoiding the sing-in,
• Avoidance of triggers such as allergens and stress,
• Regular use of emollients - they keep theskin hydrated , which is extremely important both in the calmphases and in the stages of exacerbation of the condition,
• It is recommended that the showers be lukewarm and not toohot.
• Some detergents and fragrances may irritate the skin,
• It should be approached with great care to cosmetics - it is good to avoid the use of soaps and creams with an alcohol content
• Baths can be made that relieve itching

For the finale, we'll debunk afew myths that are going on on social media aboutatopic skin:

• Atopic dermatitis is infected - perhaps this idea has spread due to the redness and itching it causes, but as we explained above, the causes of its appearance are internal;
• Children "grow it" - in some cases it is true, in others it is not;
• Corticosteroids are the best treatment - corticosteroids are used to suppress the reaction of the immune system and relieve redness and itching. It is good to use them in more severe cases and for a limited period [ref.11] from time to time, as it is mandatory to be with a doctor's prescription;
• Pets predispose to the appearance of atopic dermatitis - there are numerous studies in this direction and the topic is controversial. In general, there is no conclusive data [ref.12] for a negative effect, and there is even research showing that cohabitation at an early age lowers the risk of developing the disease.