An insidious disease is any disease that comes on slowly and does not have obvious symptoms at first. The person is not aware of it developing.
Stedman's Online Medical Dictionary. Available at: www.stedmansonline.com/content.aspx?id=mlrI1400010956&termtype=t. Accessed April 21, 2015.
Update Date 4/11/2015
Updated by: Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.