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NAILed It!

Nails can be a window into internal diseases including end organ disease and infections.

Systemic diseases can impact the integrity of the nail matrix, the germinative part of the nail apparatus —likened to the “engine of the car”. This can further impair nail growth and the attachment of the nail plate to the nail bed. Mechanical trauma, chemotherapy, stress on the body (childbirth, major injury) and viral infections (hand-foot-mouth disease) can all lead to temporary stoppage of the nail matrix growth.


The nail bed lying underneath the nail plate is embedded with thin blood vessels running longitudinally. Trauma or blockage to these fine blood vessels can result in splinter hemorrhages (red linear streaks in the nail). In addition to external trauma, psoriasis and onychomycosis (fungal disease of the nail), endocarditis (infection of the heart valves) and vasculitis are internal diseases that can result in splinter hemorrhages.


The “half moon” of the fingernail is called the lunula (latin for “little moon”), which normally abuts the proximal nail fold and appears an opaque. A red lunula may be a cause of concern for various autoimmune conditions, such as lupus, rheumatoid arthritis and dermatomyositis. A bright red lunula can also be seen in the following internal diseases: liver failure/cirrhosis, carbon monoxide poisoning, heart failure and COPD.


The curvature of the nail plate itself, called clubbing, can be a helpful clue for underlying pulmonary disease. To assess for clubbing, hold the two opposing fingers back against each other. A diamond-shaped space (a “window”) should normally appear between the nails of the two fingers. In clubbing, however, this “window” is often absent.

Yellow discoloration of the nails can be due to a various internal and external causes. Occupational and grooming practices are examples of such external causes. Amyloidosis, fungal infection, vitamin deficiencies, congenital diseases, medications, diabetes, as well as, thyroid, liver, kidney and pulmonary disease are examples of internal causes of yellow nail discoloration.

External causes (“outside - in”):


Frequent use of nail polish can lead to a yellow staining of the nail plate. The dye in the nail lacquer interacts with the keratin of the nail plate causing a yellow discoloration and brittleness. Polish remover can further induce nail yellowing by allowing the dissolved nail polish to closely adhere to the nail plate. Some have linked resorcinol as an ingredient in many nail lacquers as the culprit for the pale orange or yellowish-red discoloration of the nail. The yellow staining is typically at the distal part of the nail plate and resolves after refraining from frequent nail polish use. Applying a clear base coat and avoiding consistent use of dark colors are helpful tips to help prevent yellow nail discoloration. A dermatologist can perform a nail clipping of the distal nail plate to evaluate for and rule out other cause of yellow discoloration including nail dystrophy and/or fungal nail disease.


Heavy smokers may develop yellow staining of the nail as a result of nicotine deposit. Collaborative effort with a dermatologist and an internal medicine physician of this tell tale sign of long-term tobacco use can further help identify and screen for tobacco-related diseases, such as lung cancer, heart disease and COPD.


Carotenemia, most commonly seen in the pediatric population, results in yellowing of the skin and nails as a result of high levels of beta-carotene in the blood. Classically due to excessive dietary carotenoid intake, may also be a result, less commonly, of metabolic disease. Counseling on decreasing intake of foods with high levels of carotenoids, such as carrots, cabbage, asparagus, among others, by a dermatologist is essential in treatment of this condition.

Internal causes (“inside-out”)

Nail dystrophy and yellow nail discoloration is frequently encountered in diabetics. The most common cause is fungal nail infections. Diabetics are more susceptible to fungal or yeast nail infections which leads to a white, yellow or green discoloration in addition to a marked thickening of the nail plate. Less commonly, nail discoloration in diabetics may also be a result of ischemia. Prompt recognition and treatment with topical and systemic antifungals is essential to prevent subsequent cosmetically displeasing nail dystrophy.

Toe nail fungus in diabetics is often accompanied by tinea pedis (athlete’s foot), which classically presents as fine scaling along the foot in a “moccasin” distribution with thicker white scale residing in the toeweb spaces. Treatment of both toenail and foot fungus is of utmost importance to prevent recurrence of nail disease. Foot or toenail fungal infections may be a nidus for bacterial infection of the lower legs (i.e. cellulitis), especially in diabetics. Evaluation by a dermatologist is key for both recognition and management of yellow discoloration as recurrence is high, results are variable and duration of treatment is at least three months.

Liver disease (i.e. cirrhosis, hepatitis, hepatocellular carcinoma) can cause yellowish discoloration of the skin, mucosa and the nails as a result of deposition of excess bilirubin. Management of the liver disease has been shown to help the discoloration of hair, skin and nails. The dermatologist, the “Nancy Drew” of nail diseases, searches for additional clues for underlying liver disease when evaluating yellow nail disease.

Yellow nail syndrome occurs when all fingernails and/or toenails exhibit a thickened nail plate, with yellow discoloration, loss of cuticle and an exaggerated lateral curvature. Yellow nail syndrome can be associated with pulmonary disease, such as COPD, emphysema, lymphedema, pleuritis, chronic bronchitis and pleural effusions. Classically, yellow nail syndrome occurs in adults; however, has been reported in children with congenital lung and heart disease. A nail clipping to rule out fungal elements, blood work, physical examination and a detailed clinical history are the essential initial steps by a dermatologist. Prompt referral from dermatology to pulmonology for pulmonary function testing, imaging and detailed lung examination prevents undiagnosed, poorly controlled lung disease.

[Repairing broken nail]

When experiencing a broken nail, I often recommend to cut and/or file the nail short to prevent further trauma to the nail plate. Soaking the fingernail in dilute vinegar may help prevent yeast build up in the nail folds, which if untreated may lead to painful, red swelling of the skin around the nail. I caution patients with use of nail glues such as acrylates, a common ingredient in these products. Acrylates are frequent allergens and may lead to a rash to the skin around the involved nail.

[Nail strengthening tips]

Brittle nails may be troublesome and often challenging to treat for many. My recommendations for strengthening nails include:

  1. Biotin: A vitamin supplement that can help strengthen hair and nails.

  2. Moisturization: Frequent moisturization of the nail plates and surrounding skin can prevent further impairment of the integrity of the nails.

  3. Avoid frequent hand washing: Excessive water can soften the nail plates. Wearing protective gloves can help prevent further peeling and pliability of the nail plate.

  4. Avoid chemical irritants: Gel nail polishes, acrylic nail glue, acetone nail soaks and nail polish removers can all pose harm to the integrity and strength of the nail. Acetone-free removers and avoidance of gel nail polish or acrylic nails can collectively help improve nail strength.

  5. Nail Hardeners: There are numerous over-the-counter and prescription nail hardeners. My top picks include DermaNail nail conditioner (Summers Laboratories Inc.) and Nuvail nail conditioner (prescription). Consumers should be aware that consistent and dedicated use of the nail hardeners is key for successful results.

Changes in nail strength and texture can be cosmetically displeasing. Patience is essential as finger-and toenails slowly grow and restoring the integrity of the nail can take months to years.

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