Mao-Qiang Man, MD

Credit: tdmt.org

Atopic dermatitis (AD) management efficacy for people struggling with obesity can be enhanced by countering inflammation, improving epidermal function, and losing weight, according to new findings.¹

Certain pathological features are shared by both AD and obesity, including such features as leptin resistance, insulin resistance, and inflammation. Furthermore, an increasing number of works have begun to suggest that a link between AD and obesity is evident.²

The current review article, authored by Mao-Qiang Man, MD, from the Department of Dermatology at the University of California, San Francisco, notes that obesity—defined as having a body mass index (BMI) over 30—predisposes individuals to AD and/or makes the condition worse.

“There is a growing body of evidence suggesting a link between AD and obesity, although it is not clear which causes which,” Man and colleagues wrote. “In this review, we summarize the association of obesity with AD and discuss the interlinking roots of these two conditions.”

Background and Findings

The review’s investigators first state that there is substantial evidence linking AD and obesity, although findings among such studies are not entirely consistent. In particular, they note that among children, AD appears to be more prevalent in those who are obese compared to those who are not.

The investigators add there is a known positive correlation between the presence of AD/eczema and obesity in children, and that there is a negative correlation between AD/eczema and being underweight.³ However, some research has shown that there may not be a correlation between atopic dermatitis (AD) and obesity, or that there could be a negative relationship between the two conditions.

In 1 particular study, they noted that treating AD with IL-13 antibody was found to actually improve the condition while causing an increase in body weight.⁴ Additionally, the prevalence of AD did not show a substantial difference between overweight or obese individuals and those of normal weight, for both children and adults.

Overall, the investigators wrote that many studies have indicated a correlation between AD and overweight/obesity, but the exact relationship between AD and obesity is not fully understood. This is due to the fact that it is unclear whether AD causes obesity or the other way around.

That said, certain evidence implies that obesity may have a pathogenic effect on AD, with the researchers citing several studies including 1 that showed weight gain during pregnancy ranging from 35 to 40 pounds had elevated the likelihood of AD in children by 11%.

The investigators noted that in addition to the link between AD and obesity, evidence suggests AD can play a role in the development of obesity. They point out that studies have shown that those with newly-diagnosed AD have similar BMI levels compared to those without AD but those with AD for over a year have higher BMI levels than normal controls.

Overall, the researchers state that these findings indicate that AD may contribute to an increased risk of obesity.

As far as evidence of AD’s pathogenic role in obesity, the investigators added that the cytokine TNF-α has been shown to hinder the differentiation of preadipocytes to mature adipocytes, contributing to obesity due to promotion of fatty acid and triglyceride production, as well as the growth and proliferation of adipocytes.

The team added that TNF-α and IL-1β can also lead to the increased expression of IL-34 in adipocytes, leading to decreases in glucose uptake and an increase in adipogenesis and fat accumulation in human adipocytes. They also note that higher levels of serum IL-34 are associated with higher BMI for humans.

Overall, the investigators concluded that, due to the negative impacts that AD and obesity have on one another, proper management of 1 of the 2 conditions may help alleviate the other. The team note that both are linked to one another through several different mechanisms including endoplasmic reticulum stress, resistance to insulin, immunity, leptin resistance, and epidermal dysfunction.

“Utilizing approaches to counter inflammation, improvements in epidermal function and weight loss could enhance the efficacy of AD management in patients with obesity,” they wrote. “However, further clinical studies are needed to further validate this concept.”

References

1. ^{Yang, S, Zhu, T, Wakefield, JS, Mauro, TM, Elias, PM, Man, M-Q. Link between obesity and atopic dermatitis: Does obesity predispose to atopic dermatitis, or vice versa? Exp Dermatol. 2023; 00: 1- 11. doi:10.1111/exd.14801}
2. ^{Murota H, Koike Y, Morisaki H, Matsumoto M, Takenaka M. Exacerbating factors and disease burden in patients with atopic dermatitis. Allergol Int. 2022; 71: 25- 30.}
3. ^{Lee SI, Shin MH, Lee HB, et al. Prevalences of symptoms of asthma and other allergic diseases in korean children: a nationwide questionnaire survey. J Korean Med Sci. 2001;16:155-164.}
4. ^{Johansson EK, Ivert LU, Bradley B, Lundqvist M, Bradley M. Weight gain in patients with severe atopic dermatitis treated with dupilumab: a cohort study. BMC Dermatol. 2020;20:8.}