RT Book, Section A1 Ritter, Kathryn A1 Fitch, Robert Warne A2 Knoop, Kevin J. A2 Stack, Lawrence B. A2 Storrow, Alan B. A2 Thurman, R. Jason SR Print(0) ID 1181043521 T1 Ingrown Toenail (Onychocryptosis) T2 The Atlas of Emergency Medicine, 5e YR 2021 FD 2021 PB McGraw-Hill PP New York, NY SN 9781260134940 LK accessmedicine.mhmedical.com/content.aspx?aid=1181043521 RD 2024/03/28 AB Ingrown toenail occurs from impingement and puncture of the medial or lateral nail fold epithelium by the nail plate, allowing growth into the dermis. Granulation tissue causes sharp pain, erythema, and further swelling. The granulation tissue may become epithelialized, preventing elevation of the nail above the nail groove. There is often secondary bacterial or fungal infection. Risk factors include cutting nails short, tightly fitting shoes, and trauma. Differential includes paronychia, felon, and tumor.