Peer Reviewed

Photo Essay

An Atlas of Nail Disorders, Part 3

Alexander K. C. Leung, MD
Clinical Professor of Pediatrics, University of Calgary; Pediatric Consultant, Alberta Children’s Hospital, Calgary, Alberta, Canada

Benjamin Barankin, MD
Dermatologist, Medical Director and Founder, Toronto Dermatology Centre, Toronto, Ontario, Canada

Kin Fon Leong, MD
Pediatric Dermatologist, Pediatric Institute, Kuala Lumpur General Hospital, Kuala Lumpur, Malaysia

Amy Ah-Man Leung, MD
Resident Physician, Department of Family Medicine, University of Alberta, Edmonton, Alberta, Canada

Leung AKC, Barankin B, Leong KF, Leung AA-M. An atlas of nail disorders, part 3. Consultant. 2020;60(1):16-18. doi:10.25270/con.2020.01.00001

EDITOR’S NOTE: This article is part 3 of a 15-part series of Photo Essays describing and differentiating conditions affecting the nails. Parts 4 through 15 will be published in upcoming issues of Consultant. To access previously published articles in the series, visit the Consultant archive at and click the “Journals” tab.


Leukonychia refers to white discoloration of the nail. The term leukonychia is derived from the Greek words leuko, meaning white, and onyx, meaning nail. The condition results from defective keratinization of the nail matrix with persistence of foci of the parakeratotic cells with immature large nucleus, keratohyalin granules, and dissociation of the keratin bundles in the nail plate.1,2 The resulting diffraction of light from large keratohyalin granules and parakeratotic cells prevents the visualization of the underlying vascular nail bed and accounts for the clinically white opacification of the nail.2-6

Clinically, leukonychia can be classified based on the extent of the white discoloration as leukonychia totalis (whitening of the entire nail), leukonychia partialis (incomplete whitening of the nail) (Figure 1); leukonychia striata, also known as transverse striata or Mees lines (whitening of the nail in striae or bands that run parallel to the nail base); and leukonychia punctata, also known as punctate leukonychia (whitening of the nail in spots) (Figure 2).2,3 The white discoloration is unaffected by pressure and moves distally with growth of the nail.

Fig 1
Figure 1.

Fig 2
Figure 2.

The exact incidence of leukonychia is not known. Suffice it to say, it is a relatively uncommon condition.

Of the 4 types of leukonychia, punctate leukonychia is the most common type.7 Leukonychia is asymptomatic and is often an incidental finding.

Leukonychia can be congenital or acquired. Most cases are idiopathic. Congenital leukonychia can be inherited in an autosomal dominant or recessive fashion and often presents as leukonychia totalis.2,8 Some cases can be attributed to mutations in the phospholipase C delta 1 gene (PLCD1) on 3p21.3-3p22.2.2,9 A chromosomal mutation mapping to 12q13, a region coding for type II cytokeratins and hand keratins, has also been described.9 Congenital leukonychia can also be a manifestation of certain syndromes, including Bart-Pumphrey syndrome, Bauer syndrome, Heimler syndrome, Lowry-Wood syndrome, Vohwinkel syndrome, LEOPARD syndrome, and FLOTCH syndrome.2,3,7,8

Causes of acquired leukonychia include repeated trauma to the nail, drugs (eg, retinoids, corticosteroids, sulfonamides, pilocarpine, cytotoxic drugs), infections (eg, onychomycosis, HIV, measles, malaria, leprosy), systemic diseases (eg, vitiligo, alopecia areata, diabetes mellitus, cirrhosis, renal failure, cardiac failure, Kawasaki disease, hypoparathyroidism, hyperthyroidism, ulcerative colitis, psoriasis), tumors of the nail matrix (eg, onychopapilloma, subungual epidermoid inclusion), malignancies (eg, Hodgkin lymphoma), heavy metal poisoning (eg, thallium, arsenic) or malnutrition.1,2,6,10-13 Congenital leukonychia typically manifests at birth or early infancy whereas acquired leukonychia typically presents in childhood.7

Treatment should be directed at eliminating the underlying cause if possible. For acquired leukonychia, elimination of the underlying cause may lead to normalization of the discoloration.7 Some cases of congenital leukonychia may show gradual improvement with time.2


  1. Gregoriou S, Banaka F, Rigopoulos D. Isotretinoin-induced transverse leuconychia. J Eur Acad Dermatol Venereol. 2016;30(2):385-386. doi:​10.1111/jdv.12819
  2. Pakornphadungsit K, Suchonwanit P, Sriphojanart T, Chayavichitsilp P. Hereditary leukonychia totalis: a case report and review of the literature. Case Rep Dermatol. 2018;10(1):82-88. doi:10.1159/000488522
  3. Canavan T, Tosti A, Mallory H, McKay K, Cantrell W, Elewski B. An idiopathic leukonychia totalis and leukonychia partialis case report and review of the literature. Skin Appendage Disord. 2015;1(1):38-42. doi:10.1159/​000380956
  4. Dlova NC, Tosti A. Idiopathic acquired true total and subtotal leukonychia: report of two cases. Int J Dermatol. 2014;53(4):e261-e263. doi:10.1111/ijd.12295
  5. Kim SW, Kim MS, Han TY, Lee JH, Son S-J. Idiopathic acquired true leukonychia totalis and partialis. Ann Dermatol. 2014;26(2):262-263. doi:10.5021/ad.2014.26.2.262
  6. Pathania YS, Budania A. Congenital leuconychia striata. Postgrad Med J. 2019;95(1126):463. doi:10.1136/postgradmedj-2019-136583
  7. Das A, Bandyopadhyay D, Podder I. Idiopathic acquired true leukonychia totalis. Indian J Dermatol. 2016;61(1):127. doi:10.4103/0019-5154.174193
  8. Bakry OA, Attia AM, Shehata WA. Idiopathic acquired true leukonychia totalis. Pediatr Dermatol. 2014;31(3):404-405. doi:10.1111/j.1525-1470.2012.​01826.x
  9. Howard SR, Siegfried EC. A case of leukonychia. J Pediatr. 2013;163(3):​914-915. doi:10.1016/j.jpeds.2013.04.032
  10. Berard R, Scuccimarri R, Chédeville G. Leukonychia striata in Kawasaki disease. J Pediatr. 2008;152(6):889. doi:10.1016/j.jpeds.2008.02.037
  11. Göktay F, Güneş P, Kaynak E, Güder H, Aytekin S. A case of longitudinal apparent leuconychia on the left thumbnail with an unexpected aetiology. Clin Exp Dermatol. 2016;41(5):570-572. doi:10.1111/ced.12785
  12. Halteh P, Magro C, Scher RK, Lipner SR. Onychopapilloma presenting as leukonychia: case report and review of the literature. Skin Appendage Disord. 2017;2(3-4):89-91. doi:10.1159/000448105
  13. Topal IO, Gungor S, Kocaturk OE, Duman H, Durmuscan M. Nail abnormalities in patients with vitiligo. An Bras Dermatol. 2016;91(4):442-445. doi:10.1590/abd1806-4841.20164620

NEXT: Racquet Nail

Racquet Nail

Racquet nail, also known as nail en raquette, refers to a nail deformity characterized by a flat, broad, and short nail plate, in a way that the width of the nail plate is greater than its length (Figure).1-3 The condition is usually caused by an early obliteration of the epiphyseal line of the affected digit while the periosteal growth continues, resulting in an abnormally short distal phalanx with widening of the nail bed and nail plate.2 The female to male ratio is approximately 3 to 1.2

Fig 2


Racquet nail can affect any finger or toe but typically affects the thumbs. The deformity can be congenital or acquired. The congenital form is usually inherited as an autosomal dominant trait, and both thumbs are characteristically involved.1 Genetic disorders associated with racquet nails include Rubinstein-Taybi syndrome, Larsen syndrome, Hajdu-Cheney syndrome, Brooke-Spiegler syndrome, cartilage-hair hypoplasia, acrodysostosis, and pycnodysostosis.4 Acquired causes of racquet nail include hyperparathyroidism, nail biting, acroosteolysis, psoriatic arthropathy, and systemic sclerosis with silicosis.1,3

Racquet nail often occurs in association with other nail conditions such as leukonychia, half-and-half nails, koilonychia, Muehrcke lines, trachyonychia, onycholysis, onychodermal band, and pachyonychia.1,5

The condition is asymptomatic but can be a source of embarrassment.1 Treatment is not necessary, but cosmetic surgery may be considered for cosmesis.


  1. Baran R, Turkmani MG, Mubki T. Acquired racquet nails: a useful sign of hyperparathyroidism. J Eur Acad Dermatol Venereol. 2014;28(2):257-259. doi:10.1111/jdv.12187
  2. Richert B, Choffray A, De La Brassinne M. Cosmetic surgery for congenital nail deformities. J Cosmet Dermatol. 2008;7(4):304-308. doi:10.1111/​j.1473-2165.2008.00410.x
  3. Vetrichevvel TP, Renita L, Shobana S, Anandan S. Acquired racquet nails in Erasmus syndrome. Int J Dermatol. 2010;49(8):932-933. doi:10.1111/​j.1365-4632.2010.04490.x
  4. Leung AKC, Leung AAC. Evaluation and management of short stature in children. Consultant. 2018;58(8):195-208, 210.
  5. Daughters DB, Maibach HI. Exaggerated onychodermal band associated with unilateral racket thumb nail. Acta Derm Venereol. 1976;56(1):73-75.

NEXT: Koilonychia


Koilonychia, also known as spoon-shaped nail or concave-shaped nail, is characterized by a centrally depressed nail plate and upward eversion of the nail plate laterally (Figures 1 and 2).1-4 The term koilonychia is derived from the Greek words koilos, meaning spoon, and onyx, meaning nail. The thumbnail, index fingernail, and middle fingernail are preferentially affected.4 Affected nails are often brittle and thin.4

Fig 1
Figure 1.

Fig 2
Figure 2.

Koilonychia can be idiopathic, hereditary, or acquired.3 Isolated koilonychia in children is usually idiopathic and can be a normal finding in infants.4,5 Hereditary causes include ectodermal dysplasias, trichothiodystrophy, LEOPARD syndrome, and nail-patella syndrome.1 Familial koilonychia is usually inherited as an autosomal dominant trait with a high degree of penetrance.4,6,7

Iron-deficiency anemia is the most important acquired cause of koilonychia.4,8 Iron deficiency may result from increased physiologic demands (eg, rapid growth, menstruation, pregnancy), inadequate iron intake (eg, pica, food pads), and excessive blood loss.9,10 Koilonychia occurs in approximately 5% of individuals with chronic iron-deficiency anemia.1 Postcricoid esophageal web, dysphagia, and glossitis in patients with iron-deficiency anemia is known as Plummer-Vinson syndrome or Paterson-Brown-Kelly syndrome.4,8,9 Other acquired causes of koilonychia include trauma, contact with chemicals (eg, potassium hydroxide, petrol, solvents), endocrinopathies (eg, thyrotoxicosis, hypothyroidism, diabetes mellitus), metabolic disorders (eg, porphyria, hemochromatosis, deficiency in metalloenzymes or sulfur-containing amino acids), dermatosis (eg, lichen planus, psoriasis, alopecia areata, Darier disease), infections (eg, onychomycosis, syphilis), collagen vascular diseases (eg, systemic lupus erythematosus, Raynaud disease), high-altitude exposure (Ladakhi koilonychia), and carpal tunnel syndrome.1,3,4,11-13

The diagnosis of koilonychia is mainly a clinical one, based on the characteristic physical finding of a spoon-shaped nail. If doubt exists, a water drop test can be used to diagnose koilonychia.2,14 In this test, a few drops of water are placed on the nail plate with a syringe. In koilonychia, the water pools on the nail plate.2,14 Treatment of koilonychia should be directed at the underlying cause if possible.


  1. Balestri R, Rech G, Girardelli CR, Piraccini BM, La Placa M. Acute koilonychia of fingernails due to lye. Skin Appendage Disord. 2017;2(3-4):183-184. doi:10.1159/000453274
  2. Chelidze K, Lipner SR. The water-drop test for the diagnosis of koilonychia. J Am Acad Dermatol. 2017;77(6):e157-e158. doi:10.1016/j.jaad.2017.06.034
  3. Sorensen EP, Tom WL. Visual diagnosis: spoon nails and short, brittle hair in a 3-year-old boy. Pediatr Rev. 2016;37(9):e38-e40. doi:10.1542/pir.2015-0073
  4. Walker J, Baran R, Vélez N, Jellinek N. Koilonychia: an update on pathophysiology, differential diagnosis and clinical relevance. J Eur Acad Dermatol Venereol. 2016;30(11):1985-1991. doi:10.1111/jdv.13610
  5. Tully AS, Trayes KP, Studdiford JS. Evaluation of nail abnormalities. Am Fam Physician. 2012;85(8):779-787.
  6. Calleja-Algarra A, Aragón-Miguel R, Andrés-Lencina JJ, et al. Image gallery: spoon-shaped nails in an 11-year-old boy. Br J Dermatol. 2019;180(2):e34. doi:10.1111/bjd.17248
  7. Takahashi T, Yamashita K, Hatao K. Incidence of koilonychia and atrophy of the lingual papillae in a patient with iron-deficiency anemia. Int J Hematol. 2010;91(2):161-162. doi:10.1007/s12185-010-0505-0
  8. Mangla A, Agarwal N, Yu J, Telfer M. Spooning of the nails and webbing of the esophagus: koilonychia and Plummer-Vinson syndrome. Clin Case Rep. 2015;3(12):1054-1055. doi:10.1002/ccr3.419
  9. Leung AKC, Chan KW. Iron deficiency anemia. Adv Pediatr. 2001;48:385-408.
  10. Leung AKC, Hon KL. Pica: a common condition that is commonly missed—an update review [published online March 13, 2019. Curr Pediatr Rev. doi:10.2174/1573396315666190313163530
  11. Razmi T M, Nampoothiri RV, Dogra S. Koilonychia in iron deficiency. QJM. 2018;111(4):271-272. doi:10.1093/qjmed/hcx229
  12. Cho SB, Lee SH, Kim J. Koilonychia in carpal-tunnel syndrome. Clin Exp Dermatol. 2010;35(4):e145-e146. doi:10.1111/j.1365-2230.2009.03720.x
  13. Yanamandra U, Mukherji R, Patyal S, Nair V. Ladakhi koilonychia. BMJ Case Rep. 2014;2014:bcr2013202567. doi:10.1136/bcr-2013-202567
  14. Razmi T M, De D. Bead retention test in koilonychia. Indian J Dermatol Venereol Leprol. 2019;85(2):229-230. doi:10.4103/ijdvl.IJDVL_350_18