What is atopic dermatitis and its causes?
We offer you recommendations to minimize the discomfort caused by atopic dermatitis, a chronic skin condition in which stages of improvement alternate with others in which outbreaks are frequent.
Atopic dermatitis (DA), more commonly known as eczema, is a skin disorder that usually occurs in infants or young children and it can last until adolescence or even into adulthood. It is a chronic and hereditary condition; if either parent has eczema, asthma, conjunctivitis, or allergic rhinitis, the child is more likely to have eczema in his lifetime.
Many substances and conditions can act as triggers for a first episode or as aggravators if the person has dermatitis at that time. Some of these factors are other allergies, irritating substances for the skin (wool, detergents), stress, sudden changes in temperature, or very high or very low, and bacteria that can cause secondary infections in the lesions.
Causes of atopic dermatitis
Atopic dermatitis is the cutaneous manifestation of atopy; that is, certain people’s predisposition to suffer from conditions produced by immunoglobulin E (IgE). The mechanism involved is complex. IgE is a molecule of the immune system whose function is to activate cells called basophils and mast cells when the patient’s immune system detects any of the substances that cause allergies; or in certain infections.
Basophils and mast cells, after being activated, release a substance: histamine, which is ultimately responsible for all allergy symptoms: itching, inflammation, pain and which, depending on the area of the body in which it occurs, will produce more specific symptoms such as sneezing, itchy throat or eyes, a decrease in the diameter of the airways … When the attack is powerful, and the life of the patient is compromised, it is known as anaphylactic shock.
In atopic dermatitis, a series of IgE-mediated manifestations occur on the skin, causing histamine to be released and causing the itching, redness, and rashes that accompany atopic dermatitis. However, even though IgE mediates, atopic dermatitis is not an allergy to any substance or food. Simply put, the patient is more likely to suffer from the symptoms that accompany higher IgE levels; or react more quickly with cells (it is out of control).
Symptoms of atopic dermatitis
The common symptoms of atopic dermatitis are the following:
- The skin is dehydrated (xerosis) and itching (pruritus), becoming very intense.
- The skin can be very inflamed and red.
- Erosions or small bumps on the skin that ooze (release fluid) with scratching.
- If chronic eczema develops, the skin may appear very thickened.
You have to be extremely careful when scratching the lesions because minor wounds can occur that, in addition to bleeding, can become infected, which significantly hinders the injury’s improvement. This is especially important in babies and young children, as they do not understand that they should not touch the lesions, and the itch pushes them to scratch (see patient advice ).
The lesions can appear continuously or in the form of intermittent episodes, at any age, and disappear at any moment to not relapse again.
Types of atopic dermatitis
Although the lesions are very similar, at the diagnostic level, atopic dermatitis is divided according to the age of the patient:
It is the most frequent age of onset. Generally, the appearance of the injuries suggests that the damage is more severe than it is. When eczema begins to appear in babies, it can be of the seborrheic eczema type (see next section), eventually evolving into a form of atopic eczema.
The typical locations of eczema in infants are the face, trunk, and extremities. They usually appear in the form of red, swollen plaques or patches (they have fluid under the surface) that itch and ooze and that, due to the unconscious scratching of the lesions by the baby, can become infected.
Many of the causes of eczema in infants end up disappearing before the year and a half of life. And although they can reappear at any time, the intensity may be less.
For those babies who continue to suffer from eczema, the pattern of lesions changes. It is what is known as infantile atopic dermatitis.
Childhood atopic dermatitis
After one and a half or two years of age, the lesions develop more frequently in the flexures (skin folds) since they are areas very prone to this type of condition: the fold does not allow air and light to dry the lesion, and humidity favors its appearance and permanence. Blisters are more common than in infant dermatitis.
The areas where atopic dermatitis most often develops at these ages are:
- The inner folds of the elbows.
- The back folds of the knees.
- The folds of the mouth’s corners.
The itching is very intense, and scratching favors the appearance of wounds and scabs.