Sienna Biopharmaceuticals, Inc.

Power of Attorney

Know all by these presents, that the undersigned hereby constitutes
and appoints each of (i) the Chief Executive Officer of
Sienna Biopharmaceuticals, Inc., a Delaware corporation (the "Company"),
who is currently Frederick C. Beddingfield III, (ii) the Company's
Chief Financial Officer, who is currently Alexander Azoy, and (iii)
the Company's General Counsel, who is currently Timothy K. Andrews,
and their respective successors (including anyone serving in such
capacities on an interim or acting basis), signing singly, with full powers
of substitution, as the undersigned's true and lawful attorney-in-fact to:

1.	prepare, execute in the undersigned's name and on the
undersigned's behalf, and submit to the U.S. Securities and
Exchange Commission (the "SEC") a Form ID, including amendments
thereto, and any other documents necessary or appropriate to
obtain codes and passwords enabling the undersigned to make
electronic filings with the SEC of reports required by Section
16(a) of the Securities Exchange Act of 1934 or any rule or
regulation of the SEC;
2.	execute for and on behalf of the undersigned, in the
undersigned's capacity as an officer and/or director of the
Company, Forms 3, 4, and 5 and any amendments thereto in
accordance with Section 16(a) of the Securities Exchange Act of
1934 and the rules thereunder;
3.	do and perform any and all acts for and on behalf of the
undersigned which may be necessary or desirable to complete and
execute any such Form 3, 4, or 5, complete and execute any
amendment or amendments thereto, and timely file such form with
the SEC and any stock exchange or similar authority; and
4.	take any other action of any type whatsoever in connection with
the foregoing which, in the opinion of such attorney-in-fact,
may be of benefit to, in the best interest of, or legally
required by, the undersigned, it being understood that the
documents executed by such attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such
form and shall contain such terms and conditions as such
attorney-in-fact may approve in such attorney-in-fact's
discretion.
      The undersigned hereby grants to each such attorney-in-fact full
power and authority to do and perform any and every act and thing
whatsoever requisite, necessary, or proper to be done in the exercise
of any of the rights and powers herein granted, as fully to all
intents and purposes as the undersigned might or could do if
personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or
such attorney-in-fact's substitute or substitutes, shall lawfully do
or cause to be done by virtue of this power of attorney and the
rights and powers herein granted. The undersigned acknowledges that
the foregoing attorneys-in-fact, in serving in such capacity at the
request of the undersigned, are not assuming, nor is the Company
assuming, any of the undersigned's responsibilities to comply with
Section 16 of the Securities Exchange Act of 1934.
	This Power of Attorney shall remain in full force and effect
until the undersigned is no longer required to file Forms 3, 4, and 5
with respect to the undersigned's holdings of and transactions in
securities issued by the Company, unless earlier revoked by the
undersigned in a signed writing delivered to the foregoing attorneys-
in-fact.
	IN WITNESS WHEREOF, the undersigned has caused this Power of
Attorney to be executed as of this 21 day of March, 2019.

/s/ Alexander Azoy
By: Alexander Azoy