JMIR Publications

ABSTRACT

Background:

The skin is a dynamic ecosystem of microbes and the source of many chemical compounds that affect human health. Skin-microbiome interactions can cause persistent, psychosocially devastating body smell despite good hygiene. Since odor production is often transient, depending on diet, stress, other hormones and environmental factors, malodors may not be present during medical examinations. Patients with odor complaints can be, therefore, diagnosed as having body dysmorphic disorder (aka dermatological non-disease) and referred for psychological evaluations. Development of simple at-home tests and virtual care programs could improve the diagnosis and management of socially debilitating malodor conditions.

Objective:

The aim of this fully virtual study was to assess potential effectiveness of at-home gut microbiome testing in the diagnosis and management of idiopathic body odor and 'People are Allergic to Me' (PATM) syndrome.

Methods:

Participants of prior Metabolic Body Odor (MEBO) and PATM studies and online support groups were contacted by e-mail or via social media. The 112 individuals from 21 countries who consented to participate were mailed test kits for at-home collection of gut microbiome samples. Subjects completed an online survey (specially developed for this study) addressing their symptoms and other quality of life indicators at baseline and after sampling. Stool samples were collected after flare-ups or symptom improvements and mailed to the lab to be processed and analyzed. We evaluated between-group differences in symptom severity as well as symptom improvement observations for the same individuals. For differential abundance testing of microbial taxa, we performed nonparametric statistical analyses using Mann–Whitney U tests for unpaired samples and Wilcoxon Signed-Ranks test for paired samples.

Results:

The findings of the present study show that levels of bacteria previously associated with cutaneous body odor were significantly elevated in gut samples (P value = .0015 for Active vs. Regression/Remission groups, P value = .01 for those experiencing symptoms most or all the time vs. those who had symptoms sometimes, rarely or never, and P value = .00007 for improvement of symptoms in the same individuals). Changes in microbial diversity were significant for only between- but not within-subject comparisons.

Conclusions:

We found that changes in the gut microbiome composition affect MEBO/PATM severity. In particular an increase in intestinal bacteria producing odor when abundant in the axillary region was associated with increased intensity of self-reported symptoms. The changes were consistent in the within-group and between-group analyses. Our findings provide support for remote and decentralized clinical studies of malodor conditions, demonstrating that it is feasible to collect patient-reported outcomes (PROs) online. Supplementary sample collection procedures may help to meet established research quality standards. Clinical Trial: NCT03582826