Eczema Pathology
National Eczema Association is an excellent place to start: https://nationaleczema.org/
Eczema refers to a family of inflammatory skin conditions that lead to dry, intensely itchy skin, often accompanied by rashes, small blisters, or scaly patches. The most common form is atopic dermatitis, which frequently begins in childhood, though it can persist into adulthood or appear later in life.
There are seven recognized types, including:
- Atopic dermatitis (most prevalent)
- Contact dermatitis
- Dyshidrotic eczema
- Nummular eczema
- Seborrhoeic dermatitis
- Stasis (or varicose) dermatitis
- Neurodermatitis National Eczema AssociationNational Eczema Association
Some types, like dyshidrotic eczema, typically manifest as clusters of small, itchy blisters on the hands and feet.
In healthy skin, the outermost layer acts as a barrier to prevent water loss and protect against irritants, allergens, and microbes. In people with eczema, this barrier is weakened—often due to mutations in skin barrier proteins like filaggrin. As a result, moisture escapes more easily, and harmful substances can penetrate the skin more readily.
Once the skin barrier is compromised, the immune system becomes hyper-responsive. This leads to persistent inflammation involving T-helper (Th2) cells, cytokines like IL-4 and IL-13, and the recruitment of other immune cells. These immune reactions cause the hallmark signs of eczema: redness, itching, swelling, and sometimes weeping or crusting lesions.
Scratching, a natural response to the intense itching, further damages the skin and perpetuates the inflammation, creating a vicious cycle. Over time, chronic scratching can lead to thickened, leathery skin—a process known as lichenification.
Eczema tends to flare periodically and can vary widely in severity. Though it’s not contagious, it significantly affects quality of life and may coexist with other atopic conditions such as asthma or allergic rhinitis.