What Your Nails Are Trying to Tell You About Your Health

3.Dark Lines Beneath the Nail

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Dark lines or spots under nails can result from injuries, like jamming a finger in a door, leading to bleeding beneath. Yet, if dark streaks appear without any trauma, it’s vital to consult a doctor at once, as this could indicate skin cancer. Termed melanonychia, these streaks raise alarm especially when on a single nail. While some marks may be benign, tied to medication, pregnancy, or ethnicity, any new or evolving line warrants a check by a healthcare provider. Subungual melanoma, a severe form of skin cancer, is the gravest concern. Early detection is key, so any unexplained dark line—particularly if it widens or darkens—must be assessed swiftly.