Fingernail Ridges, Pits, Curved Nails – Health Problems, Pictures

The nails, like every part of the body, reflects the health of a person and defects of the nail may provide an indication of underlying diseases. Some of these disorders may be early signs of disease whereas other defects arise later in the course of the disease.

Localized causes of nail defects should always be excluded before considering the defect as a sign of systemic disease. Poor nail care, excessive use of cosmetic nail products and nail fungi are common causes of nail defects. This may present as lines on the nail plate, breaking or cracking of the nail, rough nails, thick nails and/or discoloration of the nails.

Healthy Fingernails

The anatomy of the nail is further discussed under Parts of the Nail.

  • The nail plate is the visible part which is often referred to simply as the nail.
  • The sides of the nail are surrounded by the nail folds and an extension of the proximal nail fold, known as the cuticle, extends slightly onto the nail plate.
  • A crescent-shaped pale area at the proximal area of the nail plate is known as the lunula, which is an extension of the matrix.

Healthy nails are pale pink in color. This is due to the blood flow in the dermal capillaries of the nail bed. The lunula is a lighter pink to almost whitish in color.

The nail plate is a smooth convex surface. It is hard but flexible and will not crack or chip unless exposed to severe force. Changes in the curvature or lines and ridges may be due to a number of diseases. There may be associated changes in the nail color – refer to Discolored Nails.

Nails grow at a rate of approximately 0.1 mm/day or about 1 centimeter every 3 months. The nail acts as a record of certain illnesses with the longitudinal axis serving as a timeline. The position of any nail deformity, like Beau’s lines, may indicate the time of an illness.

Causes of Fingernail Ridges, Pitting and Curved Nails

Normal Lines and Ridges on the Nails

  • Longitudinal ridges (running from the cuticle to the free edge of the nail) may be due to aging and not a sign of any disease.
  • Nail beading, where the nail loses its smooth curvature, is also a normal part of aging. Excessive beading that leads to a rough surface may be linked to conditions like rheumatoid arthritis.
  • White specks and lines on the nail plate are known as striate leukonychia. It is due to airspaces within the nail plate and is not a sign of calcium deficiency.

Inflamed or Swollen Nail Fold

  • This is known as paronychia. It may involve the proximal, lateral and/or distal nail folds and is most commonly due to an infection.
    • Bacterial infections often follow trauma to the area, particularly in nail biting where the bacteria in the mouth are transferred onto the broken skin. Habitual picking or biting of the proximal nail folds may also cause recurrent paronychia along with ridges and furrows of the nails.
    • Fungal infections are commonly seen with prolonged use of acrylic nails or as secondary infections transferred from a site elsewhere on the body.
    • Constantly wet hands (occupational), and excessive manicuring are other causes of paronychia.
    • Chronic paronychia may be due to poor peripheral circulation or diabetes.
    • Redness of the proximal fold along with uneven or ragged cuticles may be due to connective tissue diseases like dermatomyositis, SLE or systemic sclerosis.

Ridges and Furrows (Grooves) on the Nails

  • Beau’s line is a transverse furrow (groove) on the nail plate (refer to the picture below).  It may be caused by a number of systemic conditions including :
    • severe infection like septicemia
    • heart attack (myocardial infarction)
    • hypotensive shock
    • hypocalcemia
    • surgery
    • immunosuppressants
    • chemotherapy
    • zinc deficiency may also be responsible for Beau’s lines. .
  • Multiple transverse ridges may be due to :
    • eczema
    • psoriasis
    • chronic paronychia
    • habitual-tic dystrophy (discussed below)
  • Ladder pattern ridges and furrows may be due to habit-tic dystrophy, which is the habitual picking or biting of the proximal nail folds. The pattern appears as many transverse ridges with longitudinal furrows across the center of the nail. Recurrent paronychia due to a bacterial infection may be noted in the medical history.
  • Longitudinal ridges and brittle nails (onychorrhexis) may be due to :
    • rheumatoid arthritis
    • lichen planus
    • Darier’s disease
    • peripheral vascular disease
  • Central longitudinal ridge may be due to deficiencies related to iron, protein or folic acid
  • Central furrow (groove) that is deep like a canal may be due to trauma, severe malnutrition and severe arterial disease.

Curved and Pitting Nails

  • Koilonychia is a spoon-shaped depression of the nail plate (refer to the picture above). It mat occur in :
    • Iron deficiency anemia
    • Systemic lupus erythematosus (SLE)
    • Raynaud’s disease
    • Diabetes mellitus
    • Lichen planus
    • Protein deficiency and prolonged exposure to certain detergents may also be responsible for koilonychia in some cases.
  • Pitting is the presence of small depressions on the nail plate.
    • Fine regular pits are (thimble pitting) and may be due to alopecia areata.
    • Larger irregular pits (coarse pitting)  may be due to psoriasis,  eczema or lichen planus.
  • Beaked nails are excessively curved nail plates resembling a bird’s beak. It may be due to :
    • Hyperparathyroidism
    • Psoriasis
    • Renal failure
    • Systemic sclerosis
  • Nail beading and digital clubbing may also affect the curvature of the nail. Digital clubbing is discussed below.

Digital Clubbing

This is a severe swelling of the fingertips causing it to look like enlarged bulbs. The Lovibond angle between the proximal parts of the nail fold and nail plate is distorted, making the nail look extremely curved or humped (refer to the picture above). Clubbing may be caused by :

  • Asbestosis
  • Berylliosis
  • Mesothelioma
  • Lung cancer
  • Suppurative lung disease (empyema, bronchiectasis, cystic fibrosis)
  • Sarcoidosis
  • Congenital heart disease
  • Infective endocarditis
  • Inflammatory bowel disease
  • Biliary cirrhosis
  • Thyrotoxicosis (hyperthyroidism)
  • Familial causes

Related Articles

  1. Discolored Nails – Causes of Spots, Lines, Streaks Color Changes
  2. Thickened (Thick) and Rough Fingernails and Toenails Disorders
  3. Parts of the Nail
  4. Acrylic Nail Fungus


  1. Examining the Fingernails. Emedicine

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  • Sylvia

    I have read the information about nails and I am wondering what is it called when the nail gets to a certain point and the white part is uneven. Usually too my nail wants to peal at this time all the way down to the side. I thought maybe it would be considered ingrown fingernails, but I think it is something to do with the white part of my nail. I use to wear acrylic nails and I haven’t for a while now, but that is when I noticed the deformity of my nail. I really don’t know what is wrong with it. It is not a fungus, but my nail is not what it use to be.

    • Dr. Chris

      Hi Sylvia

      The possible causes are mentioned above. Apart from a nail fungus, there could also be some damage to the root and nail bed. This may be causing the uneven parts that may arise from long term use of acrylic nails. You should see your dermatologist.

  • Jessica

    Hi i have a question, and i havnt found anyone yet to help me with regards to this.

    I was born with half a thumb nail, this genetic, you would say that the other half nail bed is completly dead, yet i want to fix this.

    do you have any suggestion on what i could possibly do to improve this?



    • Dr. Chris

      Hi Jessica

      It is unlikely that this can be corrected if it is congenital (present since birth). You should speak to your dermatologist about various possibilities that would actually fall into the realm of cosmetic procedures.

  • Joy76

    A few of my nails split down the middle as soon as they grow a certain length. Only specific ones, mainly my thumb nails and one of my pinky finger nails. What causes this??

    • Hi Joy. Weakening on all nails could be due to a nutritional deficiency which cannot be ruled out entirely even though only some nails are splitting. If it is not related to a injury on those fingers then it is possible that these nails are weak for a specific reason. It could be an infection or some other reason that may not be obvious on the surface. It could even be due to some application on your nails, be it artificial nails or nail polish. You have to see a doctor who can assess the condition and make a diagnosis. As you can see from the article above, sometimes nail symptoms could be related to systemic diseases. Your doctor will advise your accordingly.

  • Lynn

    I’m nervous about my pinky nail on the left side. It’s very pitted and is not growing in correctly. I can see white area under the nail which to me indicates that it’s detached. It also looks a little crusty. It looks as if it could be psoraisis or a fungal infection. At the salon, they told me it didn’t look like an infection. I do not get acrylic nails. I have called my doctor to get a referral to a derm. That possibility of an infection is not the part that scares me. I also have problems with numbness in my leg and brisk reflexes as noted by my neurologist. I am being sent for an MRI. My biggest concern is that these two separate issues may be related. What can cause both of these issues and what can I do in the meantime while I wait? 🙁

    • Hi Lynn. Don’t get too concerned and make an assumption just yet. Fungal infections of the nail are quite common even if you don’t use acrylic nails, and this could be an infection. Of course psoriasis would also be a consideration if you have skin lesions that have been diagnosed as psoriasis. Yes, it is possible that the nail abnormality is linked to some underlying systemic disorder as you can see from the article above. However, these is no way of knowing for sure until it is assessed by a doctor. If this is the case then there is not much you can do to change the finger abnormality overnight. Rather look towards an infection and read up on simple ways to treat it until you can consult with a dermatologist.

      • Lynn

        Thank you for your feedback. My dermatologist says it is onycholysis and told me to take some supplements and not to freak out. He said it certainly was not any type of psoriasis or arthritis. Feel much better now.

        • Hi Lynn. Thanks for the feedback. Good to hear that it is a relatively minor condition and that your mind has been put to ease.

  • Alida

    I’d appreciate your input please. At varying times one or two fingernails curve/bend down as if to grow over the fingertip. Usually different nails, not always the same ones. Thanx.

  • Mandy

    This article is great but my issue wasn’t mentioned so I was hopeing you could give me some advice.
    My finger nails curve in at the sides as they grow, it’s similar to an ingrown toe nail but not that extreme. My little fingers are the worst, if I don’t cut them I’m sure they’d grow into a sort of tube shape. I would love to be able to actually grow my nails.
    Is there anything I can do to improve this? I have good levels of iron and other vitamins and trace minirals.

    • Hi Mandy. If this issue with your fingernail has always been present then it may not be due to any disease or disorders. It may rather just be due to an anatomical variation in your body. It is highly unlikely that any supplements will be able to change this and the only option you may have is to frequently cut the nail appropriately to prevent it from being an ingrown nail. Speak to your family doctor to ensure that there is no underlying problem that is causing this type of growth of your nail.

      • Mandy

        My nail problems are likely linked to my chronic pain and IBS. My doctor can’t do anything much about either my pain or IBS at this point