Past studies have suggested that there is a link between eczema and dementia. Patients with dementia have a higher prevalence of eczema than those without.
According the the World Health Organization, eczema (atopic dermatitis) is 15th among all nonfatal diseases and is the largest disease burden among all skin diseases. Eczema peaks in early childhood, reduces among young adults and the second peak is in the middle aged and older populations. Eczema has increased 2-3 fold over the past decades. It is currently estimated to occur in 3-4% in older populations.
Eczema and dementia related risk factors are diabetes, hypertension and cerebrovascular diseases.
In a recent study published in the Annals of Allergy, Asthma and Immunology, the association of eczema and dementia was explored including Alzheimer’s Disease and vascular dementia. The study authors hypothesized that patients with atopic dermatitis are more likely to develop new-onset dementia later in life than those without atopic dermatitis and that the atopic dermatitis severity-dementia risk relationship is positive.
The conclusions of the study showed that patients with eczema are more likely to develop any dementia, particularly Alzheimer’s disease, and that atopic dermatitis severity is associated with dementia risk, with moderate to severe atopic dermatitis increasing the likelihood of new-onset dementia development.
Atopic dermatitis is a systemic inflammatory disease, which further relates to the increased risk of various dementia related risk factors such as diabetes and cerebrovascular diseases. Eczema patients have higher hypertension, dyslipidemia, diabetes and smoking compared to patients without.
Eczema is a Th2 inflammatory disease and proinflammatory cytokines released during the allergic eczema response may play a crucial role in the pathophysiology of dementia and Alzheimer’s disease. The altered and dysregulated inflammatory pathway may affect the central nervous and may be involved in dementia.
Atopic dermatitis related neuroimmune changes in a vicious cycle take time to impair specific brain function and neural circuits involved in memory and cognition which may explain why dementia follows atopic dermatitis.
The risk of dementia after eczema showed an average onset of 5 years. Regular assessments in older patients is necessary in patients with atopic dermatitis.