Nails may exhibit many different abnormalities. In the condition known as koilonychia, the nails are flattened and have concavities. This condition may be associated with iron deficiency.
Review Date 4/16/2019
Updated by: Michael Lehrer, MD, Clinical Associate Professor, Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.