What Causes Ridges in Fingernails?

Ridges in fingernails can run horizontally or vertically. They are common and harmless, but some fingernail ridges—particularly horizontal ones—can indicate a health problem such as a thyroid issue.

This article will discuss the types of ridges found on fingernails, what causes them, how they can be treated, and when to see a healthcare provider.

Types of Ridges in Fingernails

Nail ridges, or small raised lines, can present in several ways, including:

• Vertically
• Horizontally
• With multiple lines
• One single ridge
• Affecting anywhere from a small part of the nail to a large part of the nail
• Affecting any number of fingernails

Nail ridging can occur with other symptoms, depending on the cause. Additional symptoms associated with some types of nail conditions include:

• Onychorrhexis: This includes vertical ridging and splitting, a single ridge or multiple ridges that may be shallow to deep.
• Trachyonychia: The subtype opaque trachyonychia typically presents as rough, vertical ridges and "sandpaper nails" (nails that appear to have been rubbed with sandpaper), affecting some or all of the nails. Nail plates may be thickened or thinned, and cuticles are often ragged and thickened. Nails may be brittle.
• Beau's lines: This is one or more horizontal, band-like depressions affecting one or multiple nails. It can lead to the separation of the nail plate and the shedding of the nail.
• Median canaliform nail dystrophy: This is a central, vertical ridge that is feathered and has a fir-tree pattern.
  

Causes of Ridges in Fingernails

Vertical fingernail ridges are common and typically harmless. They often become more noticeable with aging.

Horizontal ridges (Beau's lines) result from the nail temporarily slowing or stopping the growth and are more likely to result from a medical event or condition.

Horizontal ridges/Beau's lines can be an indication of:

Injury

• Crushing of the nail bed or base of the nail
• Trauma involving proximal nail fold
• Exposure to extreme cold

Infection

• Fungal or yeast infection
• Bacterial infection
• Viral warts

Medical Conditions

• Eczema (an inflammatory skin condition)
• Psoriasis
• Parakeratosis pustulosa (deformed nail, surrounded by red, scaly skin)
• Fever
• Severe malnutrition
• Pemphigus (causes blisters, sores, and fluid-filled bumps on the skin)
• Raynaud’s disease (causes blood vessels in the fingers to narrow in response to cold or stress)
• Heart attack
• Psychological stress
• Mumps (an acute contagious virus)
• Pneumonia (infection of one or both lungs)
• Coronary thrombosis (blood clot in the blood vessels or arteries of the heart)
• Kawasaki disease (acute inflammatory condition of unknown cause that involves inflammation in blood vessels)
• Syphilis (sexually transmitted infection)
• Hypoparathyroidism (insufficient production of parathyroid hormone)

These factors cause a temporary disruption to nail growth. The horizontal line forms from this temporary lack of growth and then moves up the nail as the nail grows.

Vertical ridging may be a result of conditions such as:

• Vitamin and mineral deficiencies, including vitamin B12, iron, zinc, or magnesium deficiencies
• Aging
• Lichen planus (swelling and irritation of the skin, nails, and mucous membranes)
• Psoriasis (an autoimmune condition that causes skin inflammation)
• Fungal nail infection
• Darier disease (a skin condition that causes wartlike blemishes)
• Habit of picking at the nails/cuticles
• Endocrine disorders, such as thyroid conditions
  
• Alopecia areata (an autoimmune disorder that causes patchy hair loss)
  

What Medications Can Cause Ridges in Fingernails?

Ridges in fingernails have been associated with some medications, particularly some types of chemotherapy (anticancer therapeutic agents).

How to Treat Ridges in Fingernails

Addressing ridges in nails starts by treating their cause.

If caused by an injury or isolated event, Beau's lines can grow out as the nail grows.

Conditions such as trachyonychia that can cause fingernail ridges often disappear without treatment. The recommended treatment is typically to wait and watch.

Some people choose to treat nail ridges for cosmetic reasons. For example, treatments available for trachyonychia include:

• Emollients (moisturizers)
• Topical treatments, such as corticosteroids
• Nail plate dressings
• Systemic treatments, such as biotin of 2.5 milligrams per day (mg/day), cyclosporine of 2 to 3.5 milligrams of drug per kilogram of body weight per day (mg/kg/day), retinoids, systemic corticosteroids, and Xeljanz (tofacitinib citrate)

These treatments can have risks and side effects. Talk to your healthcare provider about the benefits vs. the risks before starting treatment.

Are There Tests to Diagnose the Cause of Ridges in Fingernails?

To determine the cause of fingernail ridges, a healthcare provider will:

• Ask about your symptoms
• Ask about injury or other related information
• Do a physical examination

If necessary, your healthcare provider may run tests, such as:

• X-rays
• Blood tests
• Laboratory examination of parts of the nail or nail matrix (where the nail forms)

When to See a Healthcare Provider 

See a healthcare provider if you notice any changes to your nails, such as shape, texture, or color.

It's particularly important to see a healthcare provider if you have:

• Clubbed nails
• Horizontal ridges
• Blue nails
• Distorted nails
• Pale nails
• White lines
• White color under the nails
• Painful nails
• Pits in the nails
• Peeling nails
• Ingrown nails

See a healthcare provider immediately if you have:

• Splinter hemorrhages: Thin, red/reddish-brown bloodlines under the nails that run in the direction of nail growth.
• Hutchinson sign: Brownish-black area of pigmentation originating from the nail bed and nail matrix and subsequently involving surrounding skin).

Summary

Nail ridges are small, raised lines on the nail that can run vertically or horizontally. Vertical nail ridges are typically harmless. Horizontal nail ridges (Beau's lines) are more likely to be associated with a medical condition.

Nail ridges can be caused by aging, injury, infection, illness, or medical condition.

Treating nail ridges involves addressing their underlying cause. Often, ridges will clear up independently without targeted nail treatment. While treatments are available to treat some conditions that cause ridges, such as trachyonychia, it is important to weigh the benefits versus risks of these treatments.

Talk to your healthcare provider if you notice changes to your nails.