Linking Psychiatric Disorders to Atopic Dermatitis

I recently came across an article published in Frontiers in Psychiatry that studied the possible link between the three A’s and psychiatric disorders.¹ The three A’s referred to are asthma, allergies, and atopic dermatitis. The study was headed by Dr. Nian-Sheng Tzeng, a psychiatrist at Tri-Service General Hospital in Taiwan. During his time at the hospital, he observed that some patients with the three A’s appeared to have emotional issues, which sparked his recent study to clarify if these allergic diseases are associated with psychiatric disorders. Below I’ve summarized the study’s findings and its impact on people with atopic dermatitis.

A review of the study

Tzeng and colleagues combed through the Taiwan National Health Insurance Program database to identify people of all ages with and without allergic diseases. From their search, they found that within the past 15 years, there were 46,647 people with allergic diseases and 139,931 people without. Of those with allergic diseases, 10.8% developed a psychiatric condition, such as anxiety or depression. In the group without allergic diseases, there were only 6.7% of people that developed a psychiatric condition. Therefore, within this 15 year period, people with an allergic disease were 1.66 times more likely to develop a psychiatric disorder.

A look at who might be at higher risk

How does the study’s finding specifically affect people with atopic dermatitis? In general, the group of people with only atopic dermatitis and the group with allergic rhinitis plus atopic dermatitis were associated with a lower risk of psychiatric disorders. The remaining groups, including people with bronchial asthma alone, allergic rhinitis alone, bronchial asthma plus allergic rhinitis, bronchial asthma plus atopic dermatitis, and the combination of all three allergic diseases, were all associated with a higher risk of psychiatric disorders. Therefore, those people who suffer from asthma and allergies are more likely to develop a psychiatric disorder. Additional studies are needed to clarify the association between atopic dermatitis and the risk of psychiatric disorders.

Exploring reasons for this link

What can be the reason for the link between allergic diseases and psychiatric disorders? The reason for this link is still being determined, but there is some speculation. A recent online search of published studies suggests that there may be a link between inflammation and major disorders, including diabetes, Crohn’s disease, and allergies.^2,3 Inflammation may work in two different ways. On one side, it’s a sign that the body’s defenses are working properly to heal wounds or fight off infections. On the other side, in cases where inflammation may be the problem, the body continues to keep its defensive mechanisms working due to a perceived threat when there may no longer be one. In other words, the immune system may overreact and ultimately produce a negative effect. Allergy sufferers and people with psychiatric disorders are possibly feeling the effects of an overreaction of their immune system.^3-5 In fact, some research has shown that an anti-inflammatory diet may be effective in treating depression.⁶

The findings from this study are of interest to both healthcare professionals and people with allergies, including eczema. Both groups may want to consider how allergic diseases might impact a person’s emotional state.