**5. Conclusions**

Although the gut and skin microbiota of infants with early symptoms of allergy demonstrate similar α-diversity to those of healthy infants, some differences in β-diversity and the abundance of some bacteria can be seen, which may depend on the phenotype of the allergy. Moreover, the gut and the skin microbiota appear to be related to one another; however, this relationship may differ between patients with allergies and those without. These correlations might serve as indicators of the allergic state of the host.

**Author Contributions:** E.Ł.-R.–collected clinical data, interpreted data, wrote the first draft of the manuscript, participated in study design; M.G. (Marcin Goł˛ebiewski)—participated in study design, performed bioinformatics and statistical analyses, interpreted data, participated in writing; M.S.—performed experiments; T.G.—provided funding and supervised the study, M.G. (Marta Gorzkiewicz)–contributed to the final version of the manuscript, M.P.—collected clinical data, J.G. collected clinical data, A.K.—participated in study design, collected clinical data, interpreted data, participated in writing. All the authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was financed through grant from National Science Centre, Poland, award number 2017/25/B/NZ5/00141 to TG. The funder had no role in study design, analyzing data and writing the manuscript.

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Bioethics Committee at Nicolaus Copernicus U niversity in Torun, Collegium Medicum in Bydgoszcz, protocol code KB765/2017, approved 12 December 2017.

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.

**Data Availability Statement:** Sequence data generated during this project are available in the SRA database under BioProject no. PRJNA657878.

**Conflicts of Interest:** The authors declare no conflict of interest.
