From the Guidelines
Atopic dermatitis is primarily caused by a combination of genetic and environmental factors, with a family history of atopy and loss of function mutations in the filaggrin (FLG) gene being the most strongly associated risk factors.
Key Risk Factors
- A family history of atopy, with approximately 70% of AD patients having a positive family history of atopic diseases 1
- Loss of function mutations in the FLG gene, which encodes profilaggrin and plays a key role in the terminal differentiation of the epidermis and formation of the skin barrier 1
Other Potential Risk Factors
- Elevated birth weights may be a risk factor for disease development, although the effect size is likely small 1
- Being of black race appears to increase risk 1
- A higher level of parental education is a risk factor for disease, although the effect of socioeconomic status is unclear 1
- Living in urban areas may increase the risk of atopic dermatitis, but studies attempting to identify causative environmental agents have not been conclusive 1
Environmental Exposures
- The effect of exposure to pets is unclear, with conflicting data, although two recent studies have shown that cat ownership may enhance the effect of filaggrin mutations in promoting the development of AD 1
- There is no strong evidence to show that dust mite avoidance strategies prevent atopic dermatitis 1
- Early life microbial exposures, such as exposures to endotoxin, farm animals, and dogs, may protect against AD, although this is not a recommended measure due to potential associated health risks 1
From the Research
Causes of Atopic Dermatitis
The causes of atopic dermatitis are complex and multifaceted. Some of the key factors that contribute to the development of the disease include:
- Genetics: Atopic dermatitis has a strong heritability component, with certain genetic mutations, such as those affecting the filaggrin gene, increasing the risk of developing the disease 2, 3, 4
- Environmental factors: Exposure to environmental allergens and irritants can trigger the onset of atopic dermatitis 3, 5
- Skin barrier defects: Impairment of the epidermal barrier function, due to factors such as filaggrin deficiency, can promote inflammation and T cell infiltration 2, 4
- Microbiome dysbiosis: An imbalance of the skin and gut microbiota, including the overgrowth of Staphylococcus aureus, can contribute to the development of atopic dermatitis 2, 6, 4
- Immune system dysfunction: An abnormal immune response, including T helper 2 cell-mediated pathways and immunoglobulin E (IgE)-mediated sensitization, can play a role in the onset of atopic dermatitis 3, 6, 4
- Neuroinflammation: Itch and neuroinflammation can also contribute to the development and exacerbation of atopic dermatitis 4
Key Factors Contributing to Atopic Dermatitis
Some of the key factors that contribute to the development and exacerbation of atopic dermatitis include:
- Gut dysbiosis: An imbalance of the gut microbiota can lead to "leaky gut syndrome" and contribute to the development of atopic dermatitis 2
- Skin dysbiosis: An imbalance of the skin microbiota can lead to the overgrowth of pathogenic bacteria, such as Staphylococcus aureus, and contribute to the development of atopic dermatitis 2, 6
- Defects in the skin barrier: Impairment of the epidermal barrier function can promote inflammation and T cell infiltration, contributing to the development of atopic dermatitis 2, 4
- Genetic predisposition: Certain genetic mutations, such as those affecting the filaggrin gene, can increase the risk of developing atopic dermatitis 2, 3, 4