Evidence Begins to Gel for Atopic Dermatitis, Multiple Comorbid Conditions

A comprehensive review revealed "clear evidence" of associations between atopic dermatitis (AD) in adults and certain allergic, atopic, and immune-mediated conditions, as well as mental health problems, bone diseases, and skin infections.

Some evidence also supports associations between AD and substance use, attention deficit-hyperactivity disorder (ADHD), and some elements of metabolic syndrome. Less compelling evidence suggests AD has links to some cardiovascular conditions. The evidence for associations between adult AD and autism spectrum disorders, myocardial infarction, stroke, and metabolic syndrome remains inconclusive, an expert panel reported in the Journal of the American Academy of Dermatology.

"Atopic dermatitis is one of several atopic diseases, meaning that there are internal sensitivities that can help drive the disease in the organ of choice, including asthma, allergic rhinoconjunctivitis, and food allergies, among others," guideline panel co-chair Dawn M.R. Davis, MD, of the Mayo Clinic in Rochester, Minnesota, told MedPage Today. "We always knew there was an association between atopic dermatitis and the other atopic diseases, but we lacked the evidence. Fortunately, because we're getting more attention and more research is being performed in these areas, we now have data to back up our suspicions regarding the associations between atopic dermatitis and other atopic diseases."

"Thanks to research by our colleagues, we discovered several other comorbidities that we did not expect, including skin diseases like alopecia areata and urticaria, as well as mental health conditions, including depression, anxiety, and substance use," she continued. "We also have some evidence of associations with metabolic conditions, such as disorders of bone metabolism, and cardiovascular diseases."

The coalescence of data from multiple sources occurred in concert with the timetable for reviewing and updating the American Academy of Dermatology clinical guideline on AD. The amount and depth of the data provided a rationale for a separate guideline component devoted to recognition of comorbidities associated with AD. An overarching goal is to increase awareness of the associations and a state of readiness for any actionable information that future research might uncover.

"The goal of this guideline is to plant a seed in the mind of providers and to empower and validate patients, so they can have a customized, individualized, robust discussion about how their particular circumstances relate to any of the risk factors," said Davis.

Key findings and statements in the guideline include:

• The association between AD and asthma is well established, but the "atopic march" explanation remains unproven
• "Clear evidence" of an association between AD and food allergy, but estimated prevalence of food allergy in adults with AD remains low
• Epidemiologic studies "consistently show" an association between AD and alopecia areata, but limited data address severity of alopecia or response to treatment
• A pooled analysis of four studies showed that AD doubles the odds ratio of depression (self-reported or clinician-observed); reasons for the association remain unclear
• Limited evidence supports a "potential association" between AD and substance use/abuse (including smoking)
• Accumulating evidence suggests small associations between AD and hypertension, peripheral and coronary artery disease, congestive heart failure, and acute clinical events
• Evidence suggests a "small association" of adult AD with obesity and dyslipidemia; on the other hand, limited data have pointed to a possible inverse association with diabetes
• Several studies have shown associations with increased risk of osteoporosis and fracture in adults with AD, possibly linked by systemic inflammation

"To date, research on AD-associated comorbidities has focused on identifying potential associations in epidemiologic studies," the guideline authors wrote. "There is currently no conclusive evidence demonstrating that screening for comorbid conditions associated with AD improves patient outcomes. For the evidence of AD associations to be put into action, research is required on whether screening or management of these comorbidities among adults with AD beyond what is recommended for the general population is beneficial."

The comorbidities document is one of four AD guidelines that will be published over a 2-year period. Other documents will address topical therapy, systemic treatment and phototherapy, and pediatric AD.

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