What can cause nail discoloration, and when should I be concerned?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Nail discoloration can occur for many reasons, including injury, fungal infection, underlying health conditions, or certain medications. In most cases, minor discoloration resolves on its own. However, you should be concerned if the discoloration is spreading, changing in color or shape, or accompanied by symptoms like pain, swelling, thickening, or bleeding — these may signal a more serious issue that needs medical attention.

Because nail changes can point to anything from a simple bruise to a systemic condition, identifying the cause early matters. Take a free, instant, online symptom check to better understand what may be causing your nail discoloration and get clear guidance on your next steps.

Reviewed for medical accuracy: 07/15/2026

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Explanation

There are lots of reasons your nails might change color. Sometimes, a little injury can cause a bruise or dark spot on the nail, and that is usually harmless. Nail fungus might make your nail look yellow or brown. Other times, your nail might change color from the nail polish you use, or even from some medicines. In older people, simply aging or other health conditions can lead to changes in nail color. If you notice that the discoloration is not just a small spot but is getting larger, or if your nail starts to thicken, hurt, or show signs of infection like swelling or foul odor, that is a sign to consult a doctor. Also, if you see strange patterns like white spots or streaks on your nails, it might be a clue of an underlying condition. You can use Ubie's free AI-powered symptom checker to better understand your nail changes and determine whether you should seek medical care. Paying attention to these changes and talking to a healthcare professional will help you decide if the discoloration needs treatment or further testing.

(References)

Abdullah L, Abbas O. Common nail changes and disorders in older people: Diagnosis and management. Can Fam Physician. 2011 Feb;57(2):173-81. PMID: 21321168; PMCID: PMC3038811.
Iorizzo M, Starace M, Pasch MC. Leukonychia: What Can White Nails Tell Us? Am J Clin Dermatol. 2022 Mar;23(2):177-193. doi: 10.1007/s40257-022-00671-6. Epub 2022 Feb 2. PMID: 35112320; PMCID: PMC8809498.
Bellet JS. Nail discoloration in pediatric skin of color patients. Pediatr Dermatol. 2021 Nov;38 Suppl 2:37-41. doi: 10.1111/pde.14659. Epub 2021 Jul 15. PMID: 34263476.

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