Your Nails Could Be Silently Signaling Kidney Disease—Here's What to Watch For

Nail changes are surprisingly common in kidney disease, affecting between 52% to 82% of people with chronic kidney disease (CKD), yet most people don't realize their nails are sending an important health signal. While brittle, discolored, or oddly-shaped nails might seem like a cosmetic issue, they can actually reflect serious problems happening inside your kidneys. Unlike fatigue or muscle cramps—the vague symptoms most people associate with kidney disease—nail changes are visible markers that doctors and patients can spot early, making them worth paying attention to.

What Nail Changes Are Most Common in Kidney Disease?

Kidney disease can trigger several distinct nail problems, each with its own appearance and underlying cause. Some nail changes are specific to how advanced your kidney disease is, while others can appear at various stages. Understanding what to look for is the first step in catching potential kidney problems before they worsen.

• Half-and-Half Nails (Lindsay's Nails): The lower half of the nail near the cuticle appears white, while the top half looks red, pink, or brown with a sharp line dividing the two colors. As many as 33% of people starting dialysis have this distinctive pattern, likely caused by anemia and blood changes that trigger melanin production.
• Pale or White Nails: The entire nail appears white or pale, reflecting low protein levels in the bloodstream. This commonly occurs in kidney disorders like nephrotic syndrome, where damaged kidney filters leak excess protein into the urine, leaving less protein available for body tissues.
• Brittle or Slow-Growing Nails: As kidney failure advances, toxic waste products build up in the blood and weaken nail strength. A small study of 43 people found that 20% of those with chronic kidney disease reported brittle nails.
• Spoon-Shaped Nails (Koilonychia): Nails become brittle and curve upward at the edges, appearing depressed in the center with raised borders resembling a spoon. About 22% of chronic kidney disease patients in one small study had this condition.
• Ridged Nails: Kidney disease disrupts mineral balance and can cause iron shortfalls, leading to ridges running from nail bed to tip (longitudinal ridging) or horizontal lines across the nail (Beau's lines). Research found that 64% of kidney disease patients had longitudinal ridging and 36% had Beau's lines.
• Absent Lunula: The white half-moon visible above the nail's cuticle disappears in as many as 56% of people with end-stage renal disease, thought to be linked to anemia common in kidney disease.
• Splinter Hemorrhages: Red, purple, brown, or black lines run vertically under the nail, caused by trapped blood streaks. Around 11% to 12% of dialysis patients report this symptom.

Why Does Kidney Disease Actually Change Your Nails?

The connection between kidney disease and nail problems comes down to several chemical and biological changes happening in your body. When kidneys fail to filter waste properly, toxic substances called uremia build up in the blood. "We're not quite sure which of these chemicals or waste products impact nail growth and nail health, but it can be a sign of progressive advanced kidney failure," explains Jonathan Barratt, Ph.D., the Mayer Professor of Renal Medicine at the University of Leicester in the UK.

Beyond uremia, kidney disease disrupts multiple body systems that nails depend on. About one in seven people with chronic kidney disease develops anemia or iron deficiency because damaged kidneys produce less erythropoietin, a hormone that signals the body to create new red blood cells. Without enough hemoglobin, nail tissue weakens, leading to brittleness or the spoon-shaped appearance some patients experience.

Kidney disease also throws off your body's balance of calcium, phosphorus, and vitamin D while contributing to malnutrition—all factors that directly affect nail strength, color, and growth patterns. Low protein levels in the bloodstream, a hallmark of certain kidney disorders, leave nails pale and weak. These interconnected problems mean your nails become a window into what's happening with your kidney function.

Are Nail Changes an Early Warning Sign You Should Worry About?

Here's the important distinction: nail changes usually aren't an early sign of kidney disease. Most nail problems develop once kidney disease has already progressed to later stages, when uremia and other complications have built up significantly. However, some nail issues like Beau's lines and splinter hemorrhages don't appear to be connected to disease progression and could show up earlier.

This timing matters because it means if you notice nail changes, your kidneys may already need attention. That said, nail abnormalities become increasingly common as kidney disease worsens. For instance, half-and-half nails and absent lunula are both more common in stage 5 chronic kidney disease (kidney failure) compared to earlier stages. About 30% of people with IgA nephropathy, a rare autoimmune kidney disease, will progress to kidney failure within 20 years of diagnosis, putting them at higher risk of developing stage 5 disease and therefore more likely to experience nail abnormalities.

The bottom line: if you notice persistent nail changes—especially multiple changes at once—it's worth mentioning to your doctor, particularly if you have other kidney disease risk factors like diabetes, high blood pressure, or a family history of kidney problems. Your nails might be telling a story your body needs you to hear.