Clinical Notes : Dermatology

94. Nail discoloration

White nail syndrome

Also known as leukonychia.

Comes in 2 variants

  • leukonychia totalis

  • leukonychia partialis

    • striata

      • Mees' lines

      • Beau's lines

      • Meurcke's lines

    • punctata

    • longitudinal


Leukonychia totalis

Whitening of the entire nail.

May be inherited as autosomal dominant or recessive (rare)

May be a clinical sign of

  • hepatic failure, cirrhosis

  • hypoalbuminaemia in nephrotic syndrome, diabetes

  • malnutrition, protein malabsorption and protein-losing enteropathies

  • hyperthyroidism

  • a side effect of sulphonamides antibiotics​

Leukonychia totalis


Leukonychia partialis

  • Leukonychia striata

    • Mees' lines

    • whitening or discoloration of the nail in bands or "stria" that run parallel the lunula (nail base).

      • This is commonly caused by physical injury or disruption of the nail matrix, such as

        • excessive tapping of the nails

        •  slamming a car door

        •  extensive use of manicure

      •  It may also occur in great toenails as a result of trauma from footwear.

    • Beau's lines

      • deep grooved lines that run side to side on fingernail or toenail

      • caused by temporary cessation of division in the nail matrix due to

        • infection

        • injury

        • chemotherapuy

        • malnutrition​

    • Muehrcke's lines

      • extend all the way accross the nail bed, and lie parallel to the lunula

      • caused by decreased protein synthesis

        • during periods of metabolic stress

        • hypoalbuminemic states such as nephrotic syndrome


Mees's lines

Beau's lines

Muehrke's lines

  • Leukonychia punctata

    • Also known as "true" leukonychia, this is the most common form of leukonychia, in which small white spots appear on the nails.

    • Picking and biting of the nails are a prominent cause in young children and nail biters. Besides parakeratosis, air that is trapped between the cells may also cause this appearance.

    • It is also caused by trauma.

    • In most cases, when white spots appear on a single or a couple of fingers or toes, the most common cause is injury to the base (matrix) of the nail.

    • When this is the case, white spots disappear after around eight months, which is the amount of time necessary for nails to regrow completely. The pattern and number of spots may change as the nail grows.​

Leukonychia punctata

  • Longitudinal leukonychia

    • Longitudinal leukonychia is far less common and features smaller 1mm white longitudinal lines visible under the nail plate.

    • It may be associated with Darier's disease (autosomal dominant dyskeratosis follicularis)

Longitudinal leukonychia


Green nail syndrome

Is caused by Pseudomonas Aeruginosa

Green nail syndrome often occurs in patients with prior nail problems, such as

  • onychomycosis

  • onycholysis

  • trauma

  • chronic paronychia

  • psoriasis

Nail disease disrupts the integumentary barrier and allows a portal of entry for bacteria.

Scanning electron microscopy of patients with GNS has shown that fungal infections create tunnel-like structures in the nail keratin, and P aeruginosa grows in these spaces.

Nails with prior nail disease that are chronically exposed to moisture are at greatest risk of developing Green nail syndrome and it is typical for only one nail to be involved.


Yellow nail syndrome

Wellow-green is also possible.

Yellow nail syndrome is believed to be due to microvascular permeability, which also accounts for its associated clinical triad:

  • hypoalbuminemia

  • pleural effusion

  • lymphedema

Yellow nail syndrome may be seen in patients with

  • bronchiectasis

  • internal malignancies

  • immunodeficiency

  • rheumatoid arthritis


​Nail bed hematoma

Among the most common causes of nail discoloration, these lesions typically appear as reddish to reddish-black, depending on the age of the bleed, and will often have streaks at the distal margin of the lesion.

Risk factors for hemorrhage include blood thinners and clotting disorders.

Subungual hemorrhages that do not grow out with the nail, or that recur in the same place, may require biopsy.


Subungual melanoma

causes black-brown discoloration of the nails, and may form a longitudinal band in the nail.

Longitudinal melanonychia is a common variant in African American individuals.

Features that increase the likelihood of melanoma include

  • family history of melanoma

  • sudden change in the appearance of the lesion

  • band width greater than 3 mm

  • pigment changes extending into the cuticle (known as Hutchinson’s sign)

  • nail plate disruption

Dermoscopy may be helpful in distinguishing nail lesions.

Nonmelanocytic lesions tend to have homogeneously distributed pigment, while melanocytic lesions contain granules of pigment in cellular inclusions.

Any suspicion of melanoma warrants a punch biopsy.


​​Medication-induced effects

Minocycline may cause bluish nail discoloration similar to that produced by infection with P aeruginosa, but it is rare for only a single nail to be involved.

In addition, pigmentation changes are often present elsewhere on the body, including

  • sclera

  • teeth

  • pinna

Another medication known to color the nails blue is colloidal silver, which is still sold as a dietary supplement or homeopathic remedy to treat a wide range of ailments.

(Of note: In 1999, the Food and Drug Administration issued a final rule saying that colloidal silver isn’t safe or effective for treating any disease or condition).

Minocycline stain

Silver nitrate stain


Glomus tumor

Another cause of blue nails is glomus tumors, relatively uncommon perivascular neoplasms that are typically found in the subungual region.

These tumors are generally accompanied by

  • localized tenderness

  • cold sensitivity

  • paroxysms of excruciating pain that are disproportional to the size of the tumor

Imaging studies may aid in the diagnosis, in addition to pathologic confirmation.

Magnetic resonance imaging is the most sensitive imaging modality. 

If a glomus tumor is present, it most often appears as a well-circumscribed T2 hyperintense lesion.


Exogenous pigmentation

Nails may become discolored due to exposure to various toxins or chemicals.

Frequent culprits include

  • eosin

  • methylene blue

  • henna

  • hair dye

  • tobacco

Nicotine stain

Nail polish stain

Henna stain


In the OOH setting treatment would be directed at immediate symptoms of underlying pathology.

Refer back to the patient's own GP and specialist dermatologist where appropriate.


Tüzün Y, Karakuş Ö


 Journal of Turkish Academy of Leukonychia: 1–3. Retrieved April 2, 2017.


Chapman S, Cohen PR

"Transverse leukonychia in patients receiving cancer chemotherapy".

South. Med. J. 90 (4): 395–8. (April 1997).



Burge S M, Wilkinson JD.

"Darier-White disease: A review of the clinical features in 163 patients".

Journal of the American Academy of Dermatology. 27 (1): 40–50.


O'Neill MJF

Nail Disorder, Nonsyndromic Congenital, 3; NDNC3.

OMIM. August 11, 2011


Chiriac A, et al.

Chloronychia: green nail syndrome caused by Pseudomonas aeruginosa in elderly persons.

Clin Interv Aging. 2015;10:265-267.



Nanda S; Dorville F

"Yellow nail syndrome".

Canadian Medical Association Journal. 181 (9): 614 (2009).


Cochran  A, et al

"Subungual Melanoma: A Review of Current Treatment."

 Plastic and Reconstructive Surgery. 2014; 134(2):259-73.


De Chiara  A, et al

"Malignant Glomus Tumour: A Case Report and Review of the Literature".

Sarcoma. 7 (2): 87–91 (2003)


Copyright  © 2017 Frontline Medical Communications Inc., Parsippany, NJ, USA. All rights reserved. Unauthorized use prohibited.The information provided is for educational purposes only. Use of this Web site is subject to the medical disclaimer and privacy policy.

Ireland notes.png

CPD Quiz and Certificate

This activity attracts 1,0 CPD point

94. Nail discoloration.jpg

Scroll down the box above to view its entire content

All users who successfully complete the quiz are e-mailed a copy of their personalised CPD certificate.