Atopic Eczema: Everything you need to know about this dermatological disorder.

Atopiceczema is a chronic inflammatory disease non-contagious of the skin, caused by a combination of internal and external factors. It is characterized by periods of flare-ups interspersed with periods of remission. It affects children, adolescents, and adults alike, although the former are the most affected. It is indeed estimated that one in seven children under the age of five suffers from eczema. Several symptoms are characteristic of atopic skin.

• Skin lesions.

  Red and inflamed, eczema lesions appear during flare-ups. They primarily affect the face, neck, and neck folds in infants. In adults, eczema can manifest on almost all parts of the body. The skin at the site of the lesions is swollen and itchy. Blisters appear, which then rupture spontaneously or due to scratching. The skin then forms crusts that sometimes become chronic lesions after healing.

• Itching.

  As mentioned above, eczema lesions are accompanied by a significant itching sensation. This itching leads to sleep disturbances and sometimes mood irritability. Some tricks fortunately allow to alleviate the itchiness.

• Extremely dry skin.

  An atopic skin is constantly very dry and uncomfortable, even outside of flare-up periods. This extreme dryness is called xerosis. Emollients play a key role in managing eczema, as they help to alleviate this dryness and discomfort.

Atopic eczema has a origin genetic. Studies have indeed shown that this form of eczema is often associated with mutations on the genes coding for filaggrin and other proteins essential to the integrity of the stratum corneum. Filaggrin is notably incorporated into the lipid envelope and interacts with keratin filaments. A lack of filaggrin in the stratum corneum is associated with greater transepidermal water loss (TEWL) and a higher capacity for allergens to penetrate the skin. This skin is generally more dry, more permeable, and less protected.

Furthermore, approximately 70 to 80% of individuals with atopic eczema have an abnormally high production ofimmunoglobulin E (IgE), antibodies, in response to environmental allergens. When a person is sensitive to an allergen, their immune system produces IgE specific to that allergen. These IgE are attached to receptors found on mast cells, immune cells primarily located in connective tissues. Consequently, any exposure to this allergen causes it to bind to the IgE and triggers the release of histamine, a chemical mediator, from the granules contained in the mast cells. This then initiates a cascade of reactions leading to the typical inflammation of eczema, characterized by redness and itching.

In most cases, eczema is a benign health condition. However, there are complications that, although rare, can be avoided by preventive measures. One of these complications is generalized eczema, also known as erythroderma. Eczema is considered generalized when the lesions spread. They sometimes cover up to 90% of the body. In addition to the usual redness and itching, edema can also develop. This form of eczema constitutes a dermatological emergency and sometimes requires hospitalization.

It is also possible that lesions fromeczema may open and become infected. Microorganisms such as the herpes virus, the staphylococcus aureus bacteria, or the fungus candida albicans can colonize the wound, leading to complications. Depending on the type of pathogen causing the infection, this can cause pain and worsen itching and redness. It is important to consult a dermatologist in case of infection so they can identify the source and prescribe the appropriate treatment (antifungals if it's a fungal infection, antivirals for viral infections, and antibiotics in case of bacterial colonization).

With appropriate management, atopic eczema can disappear in adulthood. However, most people affected by this condition experience alternating periods of flare-ups and remission. To alleviate patients and mitigate their symptoms, it is necessary for them to be monitored by a dermatologist. The treatment of atopic eczema often involves the application of topical corticosteroids, cortisone-based creams with recognized anti-inflammatory effects against eczema. It should be noted that these creams are applied only once a day to eczema lesions and only during flare-ups. However, it is recommended to use them at the onset of eczema flare-ups for quick relief.

Some dermatologists also offer phototherapy to alleviate the symptoms of eczema. UVB is generally favored, although some phototherapy sessions use a combination of UVA and UVB, or a combination of UVA and an oral psoralen, a photosensitizing medication.

Finally, some daily habits can help manage eczema more effectively. It is particularly recommended to apply an emollient to the skin at least once a day. Available in the form of milk, cream, or balm, this highly nourishing treatment helps to hydrate and feed the skin deeply to restore its hydrolipidic film, a protective aqueous-oily veil that is missing or barely present on atopic skin. The application of cold or certain natural ingredients such as aloe vera or honey can also help to soothe itching.

• GOLDENBERG G. & al. Eczema. The Mount Sinai Journal of Medicine (2011).

• BORRADORI L. & al. Dermatologie et infections sexuellement transmissibles. Elsevier Masson (2017).