To Scratch or Not to Scratch, That Is the Question

The Derms on Drugs enlist the Sultan of Scratching, Dan Kaplan from the University of Pittsburgh, to answer the age- old question - should you scratch an itch or not? 

Believe it or not, some of the most cutting-edge science on the planet is focusing on this question (you think they'd have better stuff to work on, but who are we to judge). The answer(s) are going to surprise you - turns out scratching does a lot more than just get bugs off our skin (although that part is important too).

Derms on Drugs is brought to you by Scholars in Medicine.

Guest: Daniel H. Kaplan, MD, PhD

Daniel H. Kaplan, MD, PhD is a Professor within the Department of Dermatology and Immunology, University of Pittsburgh. His research is dedicated to understanding the mechanisms that underlie skin immunity and the interplay of different immune cells types that reside in the skin.  As a graduate student at Washington University, St Louis he participated in the re-invigoration of the concept of tumor immunosurveillance by observing an increased frequency of skin tumors in immunodeficient mice. During his post-doc at Yale University, he developed a number of mouse lines with a selective deficiency of Langerhans cells (LC) and showed that these cells have the unexpected capacity to suppress tissue immune. As an Assistant and later Associate professor at the University of Minnesota, he found that LC and dermal dendritic cells have unique functions in the development of anti-pathogen responses. In 2015 he moved to the University of Pittsburgh. His laboratory is currently focused on understanding how intracellular communication mechanisms between immune cells and non-hematopoietic cells in the skin with a particular emphasis on sensory afferents modulate cutaneous immunity and skin disease. 

Resource links for this episode are available at ⁠Scholars in Medicine⁠.

1. Brain's reward circuits mediate itch relief. a functional MRI study of active scratching
2. Epidermal Mechanical Scratching-Induced ROS Exacerbates the Itch-Scratch Cycle via TRPA1 Activation on Mast Cells in Atopic Dermatitis
3. Scratching promotes allergic inflammation and host defense via neurogenic mast cell activation
4. Activation of Mast-Cell-Expressed Mas-Related G-Protein-Coupled Receptors Drives Non-histaminergic Itch
5. Mast-Cell-Derived TNF Amplifies CD8(+) Dendritic Cell Functionality and CD8(+) T Cell Priming
6. Mast Cells Initiate Type 2 Inflammation through Tryptase Released by MRGPRX2/MRGPRB2 Activation in Atopic Dermatitis