Thickened Skin (Lichenification) in Atopic Dermatitis
Chronic atopic dermatitis (AD) can cause patches of thickened skin. The thickened skin is also called lichenified, and the process is called lichenification. Lichenified skin may be darker or lighter than surrounding, unaffected skin. Lichenified skin itches all the time.1
What is lichenification?
Lichenification, the thickening of the skin that is caused by chronic scratching, appears differently on people depending on their skin tone. On white skin, lichenification may appear pink or red, while on dark skin, the lichenified areas may appear darker than the unaffected skin around them.2,3
What causes thickened skin in eczema?
A dysfunction in the immune system in people with AD causes an increased inflammatory response in the skin, particularly in response to allergens, which may be airborne, topical, or ingested. The chronic inflammation, as well as the intense itch that incites scratching, change the skin over time, creating the thickened patches or lichenification.4 The itching associated with AD is a key factor in the development of thickened skin, as the repeated scratching leads to the skin changes. Scratching also increases the risk of infection and increases the inflammation in the area.
The itch-scratch cycle and lichenification
The exact disease processes that cause itch in AD are not completely understood, but doctors know that the “itch-scratch cycle” (the skin feels itchy, which leads to scratching, which then causes the skin to feel even more itchy) perpetuates the disease. The itch appears to start before the plaques or inflammation.
What causes eczema to itch?
Research has uncovered that itch in AD is related to the close relationship between the nervous system and the skin. The nerves in the skin send an “itch” message to the brain through chemical messengers called cytokines. Researchers are studying the different mechanisms related to itch, including how people with AD may have skin sensitivity that causes other sensations, such as heat or pain, to be perceived as itch.5,6
People with AD are advised to avoid the triggers that increase itchiness, such as contacts with allergens, sweat left on the skin, wool fibers, dry skin, emotional stress, and some soaps or detergents.5,6
Medications to reduce eczema inflammation
In addition, there are several medications that are designed to reduce inflammation that may help, including:
Phototherapy for eczema
Phototherapy, which uses ultraviolet light waves directed at the skin, is a second-line treatment strategy. That is, it is only recommended for use after other treatments and lifestyle approaches have failed to improve symptoms of AD. Phototherapy is sometimes used as a maintenance therapy in people with chronic AD.8
Wet wrap therapy for eczema
Wet-wrap therapy, with or without a topical corticosteroid, is another technique that can help moderate to severe AD. Wet- wrap therapy involves applying the medication (if using) and wrapping the affected area in a layer of wetted gauze, cotton, or bandages, followed by a layer of dry bandages. Wet-wrap therapy helps improve the moisture of the affected skin, improves the penetration of the topical medicine, and provides a physical barrier against scratching.7
Other symptoms of atopic dermatitis
In addition to thickened skin, AD can cause a rash, scaly patches, weepy sores, bumps or papules, blisters, and a change in skin color. Some people also experience eye symptoms or cracks behind the ears.