Is Atopic Dermatitis Only a Skin Disease, or Is It Something More?

A version of this article was originally published on Dermatology Times. This version has been lightly edited.

It’s well known that atopic dermatitis (AD) is a common, chronic, inflammatory dermatosis characterized by persistent pruritus, and its clinical presentation consists of eczema-like eruptions, including erythema, papules, and exudative lesions of a specific location, depending on the patient’s age and varying extents of skin dryness.

A group of dermatologists and dermatology students set out to provide a summary of plausible explanations for why AD may be related, with greater prevalence, to certain cardiovascular diseases, neuropsychiatric diseases (such as epilepsy, autism, attention deficit hyperreactivity disorder, and depression), autoimmune diseases (alopecia areata, vitiligo, rheumatoid diseases, type I diabetes), and obesity.

In their study, the researchers looked to demonstrate the diversity and multiplicity of diseases that may be more prevalent in AD patients based on epidemiological studies as well as underline the need for additional research into this phenomenon.

To prove their hypothesis, the authors looked for supporting literature using the PubMed database with search queries “atopic dermatitis and comorbidities”, “atopic dermatitis and cardiovascular comorbidities,” “atopic dermatitis and neurological comorbidities,” “atopic dermatitis and psychiatric comorbidities” and “atopic dermatitis and autoimmune comorbidities.”

Based on the analysis of titles and abstracts, the researchers included articles on the causes of the increased co-occurrence of atopic dermatitis, including genetic factors, immunological factors, and exposure to modifiable risk factors.

It’s been previously established that regular physical activity aids in the primary and secondary prevention of a number of chronic diseases including obesity, depression, and cardiovascular diseases, and the researchers found a study that linked adult AD with decreased physical activity in the United States.

“There are several potential causes for this,” the authors wrote. “Patients with eczematous skin lesions on their palms and soles might find it difficult to participate in a variety of activities, but also elevated skin temperature and perspiration are known flare triggers.”

Additionally, sleep disturbance and depression, which often occur in AD patients, can make it more difficult to maintain a regular exercise routine.

AD was also found to be associated with an increased incidence of eating disorders, with bulimia nervosa and binge eating disorder being the most prevalent, with the researchers explaining that incorrect administration of a systemic treatment for AD can be a factor in these issues.

Regarding cardiovascular disease, the authors found contrasting opinions in studies that looked at a possible link with AD. In one study, a 1-year history of AD in the United States was associated with a higher prevalence of coronary artery disease, angina pectoris, myocardial infarction, stroke, and peripheral vascular disease. But in a German study, AD patients experienced an elevated risk of angina pectoris, hypertension, and PVD, but not of MI or stroke.

The authors explained this by noting that a variation in endotypes and lifestyle choices between the countries could account for the observed differences.

“While the higher cardiovascular risk in psoriatic patients as, at least to some extent, a result of elevated levels of immune and cardiovascular proteins is a well-established concern, the data on AD are less researched and still emerging,” they wrote.

Some of the other research findings theorized that AD increases blood platelet activation and oxidative stress while decreasing fibrinolysis—both of which could be contributing factors to the development of thrombosis. Yet different studies indicated that the function of platelet aggregation was not impaired in AD patients, claiming that a higher activity of proinflammatory mast cells and tryptases decreased the risk of thrombosis by tryptase-mediated degradation of fibrinogen, a thrombosis mediator, and creation of a complex between heparin and tryptase, resulting in anticoagulation.

“The therapeutic significance of mentioned correlations is unknown, and there is currently no clear evidence that patients with AD require more extensive cardiovascular monitoring or therapy than is suggested for the general population,” the authors wrote. “Nevertheless, there are some attempts to implement screening for cardiovascular comorbidities.”

Based on their overall findings, the researchers concluded that AD is indeed associated with multiple comorbid allergic, cardiovascular, mental health, neurologic, autoimmune, and metabolic conditions.

Still, they warn that it’s vital to determine the extent to which this coexistence is linked to exposure to, often modifiable, risk factors, as well as genetics and immune dysregulations.

Another key point they shared is analyzing the immunology of chronic inflammation whose correction, activation, or suppression would theoretically aid in preventing the development of a variety of comorbidities.

Therefore, the study authors recommended that additional research be conducted on populations that are maximally vast and diversified to study predispositions depending on different phenoendotypes.

“It would be desirable to examine biomarkers that could be used to assess the likelihood of comorbidities in different populations,” they wrote in their conclusion. “Nonetheless, clinicians should be aware of non-allergic comorbidities associated with AD and attempt to detect them as they can be potentially undiagnosed.”

Reference

Mesjasz, A, Zawadzka M, Chalubinski M, Trzeciak M. Is atopic dermatitis only a skin disease? International Journal of Molecular Sciences. Published online January 23, 2023. doi:10.3390/ijms24010837