Meet the Providers


Christine L. Cassel, MD, FAAD

Dr. Cassel is the Chief Dermatologist at Brownstone Dermatology Associates. Dr. Cassel grew up in Hummelstown, and graduated from Lower Dauphin High School in 1991 as Valedictorian. She then attended Millersville University where she graduated Summa Cum Laude.

During her medical training at Penn State she was awarded the Dean’s Award for Scholastic Achievement. She completed residency training in Dermatology at Penn State and began her career as an attending physician where she achieved the rank of Assistant Clinical Professor of Dermatology.

Dr. Cassel has published many articles in peer reviewed journals and presented at national and state dermatological meetings. Her publications include articles on topics such as blistering disorders, herpes infections, contact allergies, soft tissue augmentation, body dysmorphic disorder, and psychodermatology.

Dr. Cassel is certified by the American Board of Dermatology, and has maintained her certification by participating in their Maintenance of Certification program.  She is a fellow of the American Academy of Dermatology.


Jessica S. Rein, MMS, PA-C

Jessica Rein joined our practice in November 2007. She is from Harrisburg, Pennsylvania. She graduated from the University of Pittsburgh at Johnstown in 2003. She then continued her education at Arcadia University where she received her Masters in Medical Science and became certified as a Physician’s Assistant.When she leaves the office, she can be found running in Hummelstown or spending time with her family.


Sean M. Gaffney, MMS, PA-C

Mr. Gaffney is the newest Brownstone Dermatology Provider and joined the practice in May of 2015. He currently resides in Mechanicsburg, Pennsylvania and is originally from Freeland, Pennsylvania.

Sean graduated from King’s College located in Wilkes-Barre, Pennsylvania in 2011 with his Bachelor’s of Science and in 2013 with a Masters in Medical Science along with certification as a Physician Assistant. During his clinical training, Sean elected to partake in a Dermatology rotation where he discovered his passion for this specialty. When Sean is out of the office, he enjoys traveling and spending time with his family.