What Is Atopic Dermatitis?

Atopic dermatitis (AD), also known as atopic eczema, is a common skin disorder affecting millions of people worldwide. While many cases are mild, AD can take a significant financial and emotional toll on patients and their loved ones.

What are the symptoms of atopic dermatitis?

AD is characterized by skin barrier function abnormalities and skin inflammation, often leading to intense itching. It is a chronic, cyclical condition with a distribution pattern that varies with age.

Who gets atopic dermatitis?

AD is the most common skin condition in children under 11 years old, affecting an estimated 15–20 percent of people in this age group at some point. However, many continue to struggle with AD in adulthood, while others experience adult-onset AD.

While current research suggests the prevalence of AD is rising, the reasons for this increase are not currently known. Additionally, its root cause and pathogenesis is poorly understood.

Are there any conditions associated with atopic dermatitis?

AD is associated with a variety of co-morbidities related to immune dysfunction, including asthma, allergic rhinitis, and food allergy. Roughly 80 percent of children with AD also develop asthma or allergic rhinitis later in childhood. Risk and severity of these disorders appear to correlate with AD severity, suggesting a common pro-inflammatory disease process.

What causes atopic dermatitis?

Current evidence reveals that AD has a complex etiology involving multiple immunologic and inflammatory pathways and environmental triggers. While environmental factors may mediate disease expression, family history and genetics play a role in individual susceptibility. Some 25 loci have been identified in association with increased risk.

The greatest known risk for developing AD is from loss-of-function mutations in the filaggrin (FLG) gene. This can lead to biophysical defects in skin barrier function, elevated pH, disorganized stratum corneum, reduced lipid content, and increased transepidermal water loss (TEWL). Of note, TEWL in newborns has been found to be a strong predictor of AD independent of FLG gene status.

Recently identified predictors of disease course include:

  • Onset of signs and symptoms occurring before 12 months of age
  • The presence of FLG gene mutations
  • Immunoglobulin E sensitization early in life

What mechanisms underlie atopic dermatitis?

One proposed mechanism attributes AD to abnormalities in cyclic nucleotide regulation of marrow-derived cells or allergenic overstimulation. However, each patient’s disease phenotype is likely to be caused by a unique interplay of several disease-specific dysregulated pathways. Additional insight into these processes may lead to safer, more effective methods of managing this condition.

To learn more about AD and emerging treatment strategies, be sure to check out our white paper.