What is the pathophysiology of atopic dermatitis (AD)?

Updated: Apr 26, 2021
  • Author: Cassandra Bradby, MD; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
  • Print
Answer

The precise mechanism for the development of eczema is unknown. Whether the clinical manifestations of atopic dermatitis (AD) are the result of violation of the epidermis and the subsequent contact between environmental irritants and immune cells, or the reverse sequence, is debatable. Nonetheless, the epidermis is the first line of defense between the body and the environment and, when intact, shields the body from a variety of irritants, allergens, and microbes. This barrier, which is maintained by differentiated keratinocytes and structural proteins, can be compromised by inheritance, trauma, decreased humidity, change in pH, and infection.

Atopic skin additionally has diminished ability to maintain water; this dry skin leads to scratching, which further contributes to the release of proinflammatory mediators. Eczema is a biphasic T-cell – mediated disease: TH2 is more prevalent in the acute phase, and TH1 predominates in the chronically affected skin. [1] Patients with atopic dermatitis have elevated serum IgE levels, peripheral eosinophilia, and overall greater numbers of immune mediators and cytokines.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!