History

Most melanonychia patients present with a history of asymptomatic hyperpigmentation of the nail plate.

A careful history should include information on medications, past treatments, hobbies, illnesses, family history, any history of trauma to the area, prior history of a biopsy of the nail unit, number of nails affected, results of any prior nail clippings sent for histologic examination, results of cultures sent for infectious organisms, change of appearance of the band (or bands) over time, and ethnic background.^[21]

In cases of subungual melanoma, the patient may describe a long-standing history of longitudinal melanonychia that recently changed in appearance. Changes that warrant concern include alteration of color, pattern, or size of the band; new onset of pain or ulceration in the site of longitudinal melanonychia;^[22]or the presence of subungual blood.^[23]

Physical Examination

Melanonychia is characterized by a tan, brown, or black discoloration of the nail unit and is often observed in the nail plate. The nail plate may be diffusely involved, or only a single longitudinal band may be present. Transverse melanonychia has also been rarely reported. One or more digits may be involved.

Levit et al identified characteristics of melanonychia that should warrant concern for subungual melanoma, and they used the acronym ABCDEF to describe them, as follows^[24]:

(A) Age: The peak incidence in the fifth to seventh decade of life. Additionally, subungual melanoma accounts for one third of melanoma cases in Asians, African Americans, and Native Americans.
(B) Brown-black band with breadth greater than 3 mm with variegated borders
(C) Change in nail band morphology despite treatment
(D) Digit involved: The thumb is more likely to be affected by subungual melanoma than the great toe; the great toe is more likely than the index finger to be affected by subungual melanoma.
(E) Extension of the brown-black pigment of the nail bed, nail matrix, and/or nail plate onto the adjacent cuticle and proximal and/or lateral nail folds (Hutchinson sign)
(F) Family or personal history of dysplastic nevus or melanoma

Careful examination of the oral and genital mucosa may provide important diagnostic clues to identify Peutz-Jeghers syndrome or Laugier-Hunziker syndrome.^{[11, 25]}

Differential Diagnoses

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Tseng YT, Liang CW, Liau JY, Chang K, Tseng YH, Chen JS, et al. Longitudinal Melanonychia: Differences in Etiology Are Associated with Patient Age at Diagnosis. Dermatology. 2017. 233 (6):446-455. [QxMD MEDLINE Link].
Andre J, Lateur N. Pigmented nail disorders. Dermatol Clin. 2006 Jul. 24(3):329-39. [QxMD MEDLINE Link].
Baran R, Kechijian P. Longitudinal melanonychia (melanonychia striata): diagnosis and management. J Am Acad Dermatol. 1989 Dec. 21(6):1165-75. [QxMD MEDLINE Link].
Sarti HM, Vega-Memije ME, Dominguez-Cherit J, Arenas R. Longitudinal melanonychia secondary to chromoblastomycosis due to Fonsecaea pedrosoi. Int J Dermatol. 2008 Jul. 47(7):764-5. [QxMD MEDLINE Link].
Harwood M, Telang GH, Robinson-Bostom L, Jellinek N. Melanoma and squamous cell carcinoma on different nails of the same hand. J Am Acad Dermatol. 2008 Feb. 58(2):323-6. [QxMD MEDLINE Link].
Parkins GJ, Burden AD, Makrygeorgou A. Psoralen ultraviolet A-induced melanonychia. Clin Exp Dermatol. 2014 Sep 30. [QxMD MEDLINE Link].
Wang YJ, Sun PL. Fungal melanonychia caused by Trichophyton rubrum and the value of dermoscopy. Cutis. 2014 Sep. 94(3):E5-6. [QxMD MEDLINE Link].
Karanth SS, Gupta A, Prabhu M. Melanonychia and mucocutaneous hyperpigmentation from hydroxyurea use for the treatment of essential thrombocytosis. Singapore Med J. 2014 Jan. 55(1):e7-8. [QxMD MEDLINE Link].
Charan S, Mishra K, Jandial A, Khadwal A, Malhotra P. Melanonychia. QJM. 2018 Jul 6. [QxMD MEDLINE Link].
Miličević T, Žaja I, Tešanović D, Radman M. Laugier-Hunziker syndrome in endocrine clinical practice. Endocrinol Diabetes Metab Case Rep. 2018. 2018:[QxMD MEDLINE Link].
Monash S. Pigmentation in the nails of the negro. Arch Dermatol. 1932 May. 105:6.
Leyden JJ, Spott DA, Goldschmidt H. Diffuse and banded melanin pigmentation in nails. Arch Dermatol. 1972 Apr. 105(4):548-50. [QxMD MEDLINE Link].
Duhard E, Calvet C, Mariotte N, Tichet J, Vaillant L. [Prevalence of longitudinal melanonychia in the white population]. Ann Dermatol Venereol. 1995. 122(9):586-90. [QxMD MEDLINE Link].
Dominguez-Cherit J, Roldan-Marin R, Pichardo-Velazquez P, et al. Melanonychia, melanocytic hyperplasia, and nail melanoma in a Hispanic population. J Am Acad Dermatol. 2008 Nov. 59(5):785-91. [QxMD MEDLINE Link].
Leung AK, Robson WL, Liu EK, et al. Melanonychia striata in Chinese children and adults. Int J Dermatol. 2007 Sep. 46(9):920-2. [QxMD MEDLINE Link].
Leaute-Labreze C, Bioulac-Sage P, Taieb A. Longitudinal melanonychia in children. A study of eight cases. Arch Dermatol. 1996 Feb. 132(2):167-9. [QxMD MEDLINE Link].
Goettmann-Bonvallot S, Andre J, Belaich S. Longitudinal melanonychia in children: a clinical and histopathologic study of 40 cases. J Am Acad Dermatol. 1999 Jul. 41(1):17-22. [QxMD MEDLINE Link].
Iorizzo M, Tosti A, Di Chiacchio N, et al. Nail melanoma in children: differential diagnosis and management. Dermatol Surg. 2008 Jul. 34(7):974-8. [QxMD MEDLINE Link].
Klausner JM, Inbar M, Gutman M, et al. Nail-bed melanoma. J Surg Oncol. 1987 Mar. 34(3):208-10. [QxMD MEDLINE Link].
Baran R, Kechijian P. Hutchinson's sign: a reappraisal. J Am Acad Dermatol. 1996 Jan. 34(1):87-90. [QxMD MEDLINE Link].
Takematsu H, Obata M, Tomita Y, Kato T, Takahashi M, Abe R. Subungual melanoma. A clinicopathologic study of 16 Japanese cases. Cancer. 1985 Jun 1. 55(11):2725-31. [QxMD MEDLINE Link].
Daniel CR 3rd, Jellinek NJ. Subungual blood is not always a reassuring sign. J Am Acad Dermatol. 2007 Jul. 57 (1):176. [QxMD MEDLINE Link].
Levit EK, Kagen MH, Scher RK, Grossman M, Altman E. The ABC rule for clinical detection of subungual melanoma. J Am Acad Dermatol. 2000 Feb. 42(2 Pt 1):269-74. [QxMD MEDLINE Link].
Braun RP, Baran R, Le Gal FA, et al. Diagnosis and management of nail pigmentations. J Am Acad Dermatol. 2007 May. 56(5):835-47. [QxMD MEDLINE Link].
Ronger S, Touzet S, Ligeron C, et al. Dermoscopic examination of nail pigmentation. Arch Dermatol. 2002 Oct. 138(10):1327-33. [QxMD MEDLINE Link].
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Media Gallery

Longitudinal melanonychia secondary to a nevus.
Pigmented longitudinal streak secondary to a nail matrix melanoma.

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Author

Chris G Adigun, MD, FAAD Director and Physician, Dermatology and Laser Center of Chapel Hill; Senior Medical Advisor, Klara

Chris G Adigun, MD, FAAD is a member of the following medical societies: American Academy of Dermatology, American Society for Dermatologic Surgery, Council for Nail Disorders, North Carolina Dermatology Association, North Carolina Medical Society

Disclosure: Serve(d) as a speaker or a member of a speakers bureau for: Sciton; OrthoDermatologics; Lumenis; PhotonMD; Galderma<br/>Received income in an amount equal to or greater than $250 from: Sciton.

Coauthor(s)

Panta Rouhani Schaffer, MD, PhD, MPH Resident Physician, Ronald O Perelman Department of Dermatology, New York University School of Medicine

Panta Rouhani Schaffer, MD, PhD, MPH is a member of the following medical societies: American Medical Association, American Public Health Association

Disclosure: Nothing to disclose.

Adam I Rubin, MD Assistant Professor of Dermatology, University of Pennsylvania School of Medicine

Adam I Rubin, MD is a member of the following medical societies: American Academy of Dermatology, American Medical Association, American Society of Dermatopathology, Women's Dermatologic Society

Disclosure: Nothing to disclose.

Specialty Editor Board

David F Butler, MD Former Section Chief of Dermatology, Central Texas Veterans Healthcare System; Professor of Dermatology, Texas A&M University College of Medicine; Founding Chair, Department of Dermatology, Scott and White Clinic

David F Butler, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Association of Military Dermatologists, Phi Beta Kappa, Texas Dermatological Society

Disclosure: Nothing to disclose.

Chief Editor

William D James, MD Paul R Gross Professor of Dermatology, Vice-Chairman, Residency Program Director, Department of Dermatology, University of Pennsylvania School of Medicine

William D James, MD is a member of the following medical societies: American Academy of Dermatology, Society for Investigative Dermatology

Disclosure: Received income in an amount equal to or greater than $250 from: Elsevier; WebMD<br/>Served as a speaker for various universities, dermatology societies, and dermatology departments.

Additional Contributors

Richard K Scher, MD Adjunct Professor of Dermatology, University of North Carolina at Chapel Hill School of Medicine; Professor Emeritus of Dermatology, Columbia University College of Physicians and Surgeons

Richard K Scher, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American College of Physicians, American Medical Association, Association of Military Surgeons of the US, International Society for Dermatologic Surgery, Noah Worcester Dermatological Society, Society for Investigative Dermatology

Disclosure: Nothing to disclose.