Additional Proxy Soliciting Materials (Form DEFA14A)

Your Vote Counts! Smartphone users Point your camera here and vote without entering a control number For complete information and to vote, visit www.ProxyVote.com Control # V91584-P47777 *Please check the meeting materials for any special requirements for meeting attendance. ACLARIS THERAPEUTICS, INC. C/O BROADRIDGE P.O. BOX 1342 BRENTWOOD, NY 11717 ACLARIS THERAPEUTICS, INC. 2026 Annual Meeting Vote by June 3, 2026 11:59 PM ET You invested in ACLARIS THERAPEUTICS, INC. and it's time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy materials for the stockholder meeting to be held on June 4, 2026. Vote Virtually at the Meeting* June 4, 2026 9:00 AM, Eastern Time Virtually at: www.virtualshareholdermeeting.com/ACRS2026 Get informed before you vote View the Notice and Proxy Statement and 2025 Annual Report online OR you can receive a free paper or email copy of the material(s) by requesting prior to May 21, 2026. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to [email protected]. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy.

Vote at www.ProxyVote.com Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click "Delivery Settings". Voting Items Board Recommends V91585-P47777 THIS IS NOT A VOTABLE BALLOT This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote these important matters. 1. Election of Directors For Nominees: 01) Anand Mehra, M.D. 02) Maxine Gowen, Ph.D. 2. To approve, on an advisory basis, the compensation of our named executive officers, as disclosed in the proxy statement accompanying the proxy card. For 3. To ratify the selection by the Audit Committee of the Board of Directors of PricewaterhouseCoopers LLP as the independent registered public accounting firm of Aclaris Therapeutics, Inc. for its fiscal year ending December 31, 2026. For NOTE: Such other business as may properly come before the meeting or any adjournment thereof.