The nail as an investigative tool in medicine: What a dermatologist ought to know

Chander Grover, Shikha Bansal

Indian Journal of Dermatology, Venereology, and Leprology 2017 83(6):635-643

The nail is an important skin appendage, but not many dermatologists are aware of the importance it receives outside our specialty. This article focuses on the nail in non-dermatological contexts. The nail is a keratinized matrix capable of continuous growth with the ability to incorporate various compounds within its structure. Therefore it can be used to monitor long-term consumption of drugs. It is also an excellent source of germ-line DNA for genetic analyses. With an increased undrstanding of nail physiology, there is now a better understanding of its connection to various pathologies as well. Nails, being peripherally placed, are easy to sample without significant discomfort to the patient, making them a valuable diagnostic tool. For this narrative review, we carried out a PubMed search using the key words "nail clipping," "nail DNA," "nail diabetes mellitus;" "nail clipping oncology," and "nail forensics". Retrieved articles were searched for information pertaining to non-dermatologic uses of nail for evaluation, which is presented in a narrative fashion. It is clear from recent literature that the nail is not just an inert skin appendage, but a dynamic window into the ever-changing metabolic and genetic milieu. We highlight the numerous roles of nail specimens, as well as point towards future research needed therein.