DermTech (DMTKQ) 8-K Entry into a Material Definitive Agreement

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

The Board of Directors

DermTech, Inc.:

We consent to the incorporation by reference in the registration statement (No.333-232181) on FormS-4/A of DermTech, Inc. (formerly known as Constellation Alpha Capital Corp.) of our report dated April 22, 2019, with respect to the balance sheets of DermTech, Inc. as of December 31, 2018 and 2017, and the related statements of operations and comprehensive loss, convertible preferred stock and stockholders’ (deficit) equity, and cash flows for each of the years in thetwo-year period ended December 31, 2018, and the related notes (collectively, the “financial statements”), which report is incorporated by reference in the Form8-K of DermTech, Inc. dated September 5, 2019. Our report dated April 22, 2019 contains an explanatory paragraph that states that the Company has suffered recurring losses from operations and has a net capital deficiency, which raise substantial doubt about its ability to continue as a going concern. The financial statements do not include any adjustments that might result from the outcome of that uncertainty.

/s/ KPMG LLP

San Diego, California

September 5, 2019