Why Do My Nails Have Deep, Horizontal Grooves or Ridges? (Beau’s Lines)

Deep horizontal grooves that run from one side of a nail to the other are often called Beau’s lines. They form when nail growth temporarily slows or pauses, leaving a visible indentation that gradually moves toward the tip as the nail continues to grow.

A single groove may follow an injury or a short period of stress on the nail. Grooves affecting several nails at the same level may reflect a broader interruption in nail growth, so the pattern, timing, and other symptoms all matter.

Quick answer

• Beau’s lines are horizontal depressions across the nail plate.
• They can appear after nail trauma, a significant illness, physical stress, nutritional disruption, or certain medical treatments.
• A groove usually becomes more noticeable as the nail grows outward.
• One affected nail often suggests a local cause, while several affected nails may warrant a broader evaluation.
• New, repeated, painful, discolored, or unexplained nail changes should be checked by a dermatologist.

What are Beau’s lines?

Beau’s lines are not simply surface texture or the fine vertical ridges that many people develop over time. They are distinct horizontal grooves caused by a temporary disruption in the nail matrix, the area under the skin where the nail is produced.

When the nail matrix slows down, the nail plate formed during that period may be thinner or indented. Once normal growth resumes, a healthier section of nail begins to emerge behind the groove. The line then moves forward as the nail grows.

The depth and width of the groove may offer clues about how significant or prolonged the interruption was, but appearance alone cannot identify the cause. A dermatologist may need to examine the nails, surrounding skin, medical history, medications, and recent illnesses before offering a diagnosis.

Common causes and triggers

Beau’s lines can be associated with several different situations. Common possibilities include:

• Direct nail trauma: An impact, repeated pressure, aggressive manicure work, or irritation near the cuticle can temporarily affect the nail matrix.
• Significant illness or fever: A major physical stressor may briefly redirect the body’s resources and slow nail production.
• Surgery or hospitalization: Recovery from a substantial medical event can sometimes be reflected in later nail growth.
• Severe emotional or physical stress: Intense stress may contribute to temporary changes in normal growth cycles.
• Nutritional disruption: A period of inadequate intake, rapid weight change, or difficulty absorbing nutrients may affect nail formation.
• Certain medications or medical treatments: Some therapies can influence rapidly growing cells, including cells involved in nail production.
• Inflammation around the nail: Skin conditions or irritation involving the nail folds may interfere with healthy growth.
• Circulation or systemic health concerns: Repeated grooves across several nails can sometimes be associated with an underlying health issue that deserves medical attention.

The number of nails involved is important. A groove on one thumbnail after an injury is different from matching grooves appearing across most fingernails without an obvious explanation.

Can you tell when the interruption happened?

Because nails grow gradually, the position of a Beau’s line may provide a rough clue about when the growth interruption occurred. A groove close to the cuticle is more recent, while one near the free edge likely formed earlier.

However, nail growth speed varies by age, finger or toe, circulation, health status, season, and individual biology. Toenails also grow much more slowly than fingernails. For that reason, trying to date a groove at home is imprecise and should not be used to determine its medical cause.

What you can do at home

Home care cannot remove an existing Beau’s line, but gentle habits may help protect the growing nail while you monitor it.

• Keep the nails trimmed to reduce snagging and splitting.
• Use a moisturizer on the nails and surrounding cuticles.
• Wear gloves during cleaning, gardening, or wet work.
• Avoid picking, scraping, or aggressively buffing the groove.
• Pause harsh manicure practices if the nail folds are irritated.
• Take clear photos every few weeks to track whether the line is moving outward with growth.
• Note any recent illness, injury, surgery, medication change, or major stressor that may help your clinician understand the timing.

Do not rely on supplements as a universal solution. Nail changes have many possible causes, and taking unnecessary supplements may not address the underlying issue. Your clinician can help determine whether nutritional testing or other evaluation is appropriate.

Professional evaluation and treatment options

Treatment depends on what interrupted nail growth. If the cause was a one-time injury or temporary illness, the groove may simply grow out over time. When inflammation, repeated trauma, medication effects, or another health concern is involved, addressing that factor may help reduce future nail changes.

A dermatologist may examine the shape, color, thickness, and distribution of the grooves. They may also ask whether the same level of indentation appears across several nails, whether toenails are involved, and whether you have symptoms elsewhere on the skin or body.

Depending on the findings, your dermatologist may recommend monitoring, changes in nail care, evaluation of nearby skin inflammation, communication with another treating clinician, or laboratory testing. The goal is not only to improve the nail’s appearance but also to understand why normal growth was interrupted.

When should you see a dermatologist?

It is worth scheduling an evaluation when Beau’s lines are new, unexplained, recurring, or affecting several nails. You should also seek care if you notice:

• Pain, swelling, warmth, or drainage around a nail.
• Dark pigment, unusual color changes, or bleeding beneath the nail.
• Nail lifting, crumbling, thickening, or rapid deterioration.
• Grooves that repeatedly return from the base of the nail.
• Changes involving most fingernails or both fingernails and toenails.
• Associated fatigue, fever, unexplained weight change, or other new symptoms.
• A recent medication or treatment change that may be affecting the nails.

A dermatologist can evaluate the pattern without assuming that every groove signals a serious condition. Many causes are temporary, but a professional examination can help separate routine nail trauma from changes that deserve further attention.

Frequently asked questions

Are Beau’s lines the same as normal vertical ridges?

No. Beau’s lines run horizontally across the nail and create a depressed groove. Vertical ridges run from the cuticle toward the tip and are often related to normal nail structure, dryness, or aging.

Will Beau’s lines disappear?

The existing groove does not flatten immediately, but it may move toward the tip as new nail grows behind it. The total time varies, especially because toenails grow more slowly than fingernails.

Can nail polish hide the grooves?

Polish may make the surface less noticeable, but it does not treat the cause. Avoid heavy buffing or repeated filing to smooth the groove because thinning the nail can make it more fragile.

Do Beau’s lines mean I have a vitamin deficiency?

Not necessarily. Nutritional disruption is one possible factor, but trauma, illness, inflammation, medications, and other stressors can also affect nail growth. Testing should be based on your history and clinical evaluation rather than appearance alone.

Why do several nails have grooves in the same place?

Matching grooves may indicate that several nail matrices slowed at about the same time. A recent illness or another whole-body stressor may be relevant, but a dermatologist should evaluate unexplained or recurring patterns.

Can a manicure cause a horizontal groove?

Yes. Repeated pressure, cutting the cuticle, forceful pushing near the nail base, or irritation from nail services may disrupt the matrix of an individual nail. Gentle nail care can help reduce repeated trauma.

This article is for educational purposes and is not medical advice. For diagnosis and personalized treatment, please book an appointment with a board-certified dermatologist.