Dermoscopy of nail pigmentations
- Antonella Tosti, MD
Antonella Tosti, MD
- Professor of Clinical Dermatology
- Department of Dermatology & Cuteneous Surgery, Miller School of Medicine, University of Miami
Nail pigmentation is most commonly caused by deposits of melanin or hemosiderin within the nail plate. It is rarely due to deposits of other pigments of endogenous or exogenous origin.
Melanin deposits result from activation or proliferation of nail matrix melanocytes and in most cases present as a longitudinal pigmented band called longitudinal melanonychia or melanonychia striata .
Nail dermoscopy (onychoscopy) can greatly improve the differential diagnosis of nail pigmentation and helps clinicians with at least minimal training in dermoscopy to distinguish benign lesions, which do not require additional examinations, from lesions that require excision for pathologic evaluation or regular follow-up [2,3].
However, dermoscopy should not be considered a substitute for pathology in the differential diagnosis of doubtful cases of longitudinal melanonychia . This topic will discuss the causes of nail pigmentation and the dermoscopic evaluation of benign and malignant pigmented nail lesions. Nail disorders are discussed separately. The dermoscopic evaluation of cutaneous and mucosal lesions is also discussed separately. Dermoscopic algorithms for skin cancer triage are also discussed separately.
●(See "Overview of nail disorders".)
- Tosti A, Piraccini BM, de Farias DC. Dealing with melanonychia. Semin Cutan Med Surg 2009; 28:49.
- Lencastre A, Lamas A, Sá D, Tosti A. Onychoscopy. Clin Dermatol 2013; 31:587.
- Piraccini BM, Dika E, Fanti PA. Tips for diagnosis and treatment of nail pigmentation with practical algorithm. Dermatol Clin 2015; 33:185.
- Jellinek N. Nail matrix biopsy of longitudinal melanonychia: diagnostic algorithm including the matrix shave biopsy. J Am Acad Dermatol 2007; 56:803.
- Tosti A, Cameli N, Piraccini BM, et al. Characterization of nail matrix melanocytes with anti-PEP1, anti-PEP8, TMH-1, and HMB-45 antibodies. J Am Acad Dermatol 1994; 31:193.
- Perrin C, Michiels JF, Pisani A, Ortonne JP. Anatomic distribution of melanocytes in normal nail unit: an immunohistochemical investigation. Am J Dermatopathol 1997; 19:462.
- Ronger S, Touzet S, Ligeron C, et al. Dermoscopic examination of nail pigmentation. Arch Dermatol 2002; 138:1327.
- Tosti A, Argenziano G. Dermoscopy allows better management of nail pigmentation. Arch Dermatol 2002; 138:1369.
- Thomas L, Dalle S. Dermoscopy provides useful information for the management of melanonychia striata. Dermatol Ther 2007; 20:3.
- Braun RP, Baran R, Le Gal FA, et al. Diagnosis and management of nail pigmentations. J Am Acad Dermatol 2007; 56:835.
- Haenssle HA, Blum A, Hofmann-Wellenhof R, et al. When all you have is a dermatoscope- start looking at the nails. Dermatol Pract Concept 2014; 4:11.
- Phan A, Dalle S, Touzet S, et al. Dermoscopic features of acral lentiginous melanoma in a large series of 110 cases in a white population. Br J Dermatol 2010; 162:765.
- Koga H, Saida T, Uhara H. Key point in dermoscopic differentiation between early nail apparatus melanoma and benign longitudinal melanonychia. J Dermatol 2011; 38:45.
- Di Chiacchio ND, Farias DC, Piraccini BM, et al. Consensus on melanonychia nail plate dermoscopy. An Bras Dermatol 2013; 88:309.
- Inoue Y, Menzies SW, Fukushima S, et al. Dots/globules on dermoscopy in nail-apparatus melanoma. Int J Dermatol 2014; 53:88.
- Murata Y, Kumano K. Dots and lines: a dermoscopic sign of regression of longitudinal melanonychia in children. Cutis 2012; 90:293.
- Tosti A, Baran R, Morelli R, et al. Progressive fading of longitudinal melanonychia due to a nail matrix melanocytic nevus in a child. Arch Dermatol 1994; 130:1076.
- Braun RP, Baran R, Saurat JH, Thomas L. Surgical Pearl: Dermoscopy of the free edge of the nail to determine the level of nail plate pigmentation and the location of its probable origin in the proximal or distal nail matrix. J Am Acad Dermatol 2006; 55:512.
- Baran R, Kechijian P. Hutchinson's sign: a reappraisal. J Am Acad Dermatol 1996; 34:87.
- Sawada M, Ishizaki S, Kobayashi K, et al. Longterm digital monitoring in the diagnosis and management of congenital nevi of the nail apparatus showing pseudo-Hutchinson's sign. Dermatol Pract Concept 2014; 4:37.
- Kawabata Y, Ohara K, Hino H, Tamaki K. Two kinds of Hutchinson's sign, benign and malignant. J Am Acad Dermatol 2001; 44:305.
- Hirata SH, Yamada S, Enokihara MY, et al. Patterns of nail matrix and bed of longitudinal melanonychia by intraoperative dermatoscopy. J Am Acad Dermatol 2011; 65:297.
- Di Chiacchio N, Hirata SH, Enokihara MY, et al. Dermatologists' accuracy in early diagnosis of melanoma of the nail matrix. Arch Dermatol 2010; 146:382.
- Astur Mde M, Farkas CB, Junqueira JP, et al. Reassessing Melanonychia Striata in Phototypes IV, V, and VI Patients. Dermatol Surg 2016; 42:183.
- Baran R. Nail biting and picking as a possible cause of longitudinal melanonychia. A study of 6 cases. Dermatologica 1990; 181:126.
- Piraccini BM, Iorizzo M, Starace M, Tosti A. Drug-induced nail diseases. Dermatol Clin 2006; 24:387.
- Finch J, Arenas R, Baran R. Fungal melanonychia. J Am Acad Dermatol 2012; 66:830.
- Kilinc Karaarslan I, Acar A, Aytimur D, et al. Dermoscopic features in fungal melanonychia. Clin Exp Dermatol 2015; 40:271.
- Cooper C, Arva NC, Lee C, et al. A clinical, histopathologic, and outcome study of melanonychia striata in childhood. J Am Acad Dermatol 2015; 72:773.
- Goettmann-Bonvallot S, André J, Belaich S. Longitudinal melanonychia in children: a clinical and histopathologic study of 40 cases. J Am Acad Dermatol 1999; 41:17.
- Tosti A, Baran R, Piraccini BM, et al. Nail matrix nevi: a clinical and histopathologic study of twenty-two patients. J Am Acad Dermatol 1996; 34:765.
- Ohn J, Choe YS, Mun JH. Dermoscopic features of nail matrix nevus (NMN) in adults and children: A comparative analysis. J Am Acad Dermatol 2016; 75:535.
- Amin B, Nehal KS, Jungbluth AA, et al. Histologic distinction between subungual lentigo and melanoma. Am J Surg Pathol 2008; 32:835.
- Schneider SL, Tosti A. Tips to diagnose uncommon nail disorders. Dermatol Clin 2015; 33:197.
- Miteva M, Fanti PA, Romanelli P, et al. Onychopapilloma presenting as longitudinal melanonychia. J Am Acad Dermatol 2012; 66:e242.
- Mun JH, Kim GW, Jwa SW, et al. Dermoscopy of subungual haemorrhage: its usefulness in differential diagnosis from nail-unit melanoma. Br J Dermatol 2013; 168:1224.
- Baran R, Simon C. Longitudinal melanonychia: a symptom of Bowen's disease. J Am Acad Dermatol 1988; 18:1359.
- Giacomel J, Lallas A, Zalaudek I, Argenziano G. Periungual Bowen disease mimicking chronic paronychia and diagnosed by dermoscopy. J Am Acad Dermatol 2014; 71:e65.
- Tosti A, Piraccini BM, Cagalli A, Haneke E. In situ melanoma of the nail unit in children: report of two cases in fair-skinned Caucasian children. Pediatr Dermatol 2012; 29:79.
- Iorizzo M, Tosti A, Di Chiacchio N, et al. Nail melanoma in children: differential diagnosis and management. Dermatol Surg 2008; 34:974.
- ANATOMY OF THE NAIL AND DISTRIBUTION OF NAIL MELANOCYTES
- CAUSES OF NAIL PIGMENTATION
- Nail pigmentation due to melanin deposition
- Nail pigmentation due to blood deposition
- EXAMINATION OF NAIL AND PERIUNGUAL TISSUES
- Types of dermatoscopes
- Limitations of nail dermoscopy
- DERMOSCOPIC PATTERNS OF NAIL PLATE PIGMENTATION
- Background color
- Arrangement of lines within brown/black bands
- Homogeneous black pigmentation
- Dots and globules
- Blood spots
- DERMOSCOPY OF NAIL PLATE FREE EDGE
- DERMOSCOPY OF PROXIMAL NAIL FOLD
- DERMOSCOPY OF THE HYPONYCHIUM
- INTRAOPERATIVE DERMOSCOPY OF THE NAIL MATRIX
- DIFFERENTIAL DIAGNOSIS OF NAIL PIGMENTATIONS
- Benign lesions
- - Ethnic-type melanonychia
- - Traumatic melanonychia
- - Drug-induced melanonychia
- - Postinflammatory melanonychia
- - Fungal melanonychia
- - Nevi
- - Lentigo
- - Onychopapilloma
- - Hematoma
- Malignant lesions
- - Melanoma
- - Bowen disease/squamous cell carcinoma
- MELANONYCHIA IN CHILDREN
- SUMMARY AND RECOMMENDATIONS