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Pigmentary mosaicism (hypomelanosis of Ito)

Julie V Schaffer, MD
Karen A Chernoff, MD
Section Editors
Moise L Levy, MD
Jennifer L Hand, MD
Deputy Editor
Rosamaria Corona, MD, DSc


The term "pigmentary mosaicism" refers to patterned hypo- or hyperpigmentation resulting from a clone of skin cells with altered ability to produce melanin. The three major clinical patterns are streaks and swirls following the Blaschko lines (figure 1), a segmental or "checkerboard" distribution, and a phylloid (leaf-like) arrangement.

This topic will discuss the epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of pigmentary mosaicism. Other inherited and acquired disorders of pigmentation are discussed separately.

(See "Incontinentia pigmenti".)

(See "Acquired hyperpigmentation disorders".)

(See "Acquired hypopigmentation disorders other than vitiligo".)

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Literature review current through: Nov 2017. | This topic last updated: Nov 29, 2016.
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  1. Cohen J 3rd, Shahrokh K, Cohen B. Analysis of 36 cases of Blaschkoid dyspigmentation: reading between the lines of Blaschko. Pediatr Dermatol 2014; 31:471.
  2. Nehal KS, PeBenito R, Orlow SJ. Analysis of 54 cases of hypopigmentation and hyperpigmentation along the lines of Blaschko. Arch Dermatol 1996; 132:1167.
  3. Ruiz-Maldonado R, Toussaint S, Tamayo L, et al. Hypomelanosis of Ito: diagnostic criteria and report of 41 cases. Pediatr Dermatol 1992; 9:1.
  4. Taibjee SM, Bennett DC, Moss C. Abnormal pigmentation in hypomelanosis of Ito and pigmentary mosaicism: the role of pigmentary genes. Br J Dermatol 2004; 151:269.
  5. Di Lernia V. Segmental nevus depigmentosus: analysis of 20 patients. Pediatr Dermatol 1999; 16:349.
  6. Metzker A, Morag C, Weitz R. Segmental pigmentation disorder. Acta Derm Venereol 1983; 63:167.
  7. Hogeling M, Frieden IJ. Segmental pigmentation disorder. Br J Dermatol 2010; 162:1337.
  8. Torchia D, Happle R. Segmental hypomelanosis and hypermelanosis arranged in a checkerboard pattern are distinct naevi: flag-like hypomelanotic naevus and flag-like hypermelanotic naevus. J Eur Acad Dermatol Venereol 2015; 29:2088.
  9. Pascual-Castroviejo I, López-Rodriguez L, de la Cruz Medina M, et al. Hypomelanosis of Ito. Neurological complications in 34 cases. Can J Neurol Sci 1988; 15:124.
  10. Happle R. Monoallelic expression on autosomes may explain an unusual heritable form of pigmentary mosaicism: a historical case revisited. Clin Exp Dermatol 2009; 34:834.
  11. Horn D, Happle R, Neitzel H, Kunze J. Pigmentary mosaicism of the hyperpigmented type in two half-brothers. Am J Med Genet 2002; 112:65.
  12. Montagna P, Procaccianti G, Galli G, et al. Familial hypomelanosis of Ito. Eur Neurol 1991; 31:345.
  13. Mirzaa GM, Campbell CD, Solovieff N, et al. Association of MTOR Mutations With Developmental Brain Disorders, Including Megalencephaly, Focal Cortical Dysplasia, and Pigmentary Mosaicism. JAMA Neurol 2016; 73:836.
  14. González-Enseñat MA, Vicente A, Poo P, et al. Phylloid hypomelanosis and mosaic partial trisomy 13: two cases that provide further evidence of a distinct clinicogenetic entity. Arch Dermatol 2009; 145:576.
  15. Happle R, Franco-Guío MF, Santacoloma-Osorio G. Phylloid hypermelanosis: a cutaneous marker of several different disorders? Pediatr Dermatol 2014; 31:504.
  16. Thapa R, Dhar S, Malakar R, Chakrabartty S. Hypomelanosis of ito-whorled hyperpigmentation combination: a mirror image presentation. Pediatr Dermatol 2007; 24:572.
  17. Restano L, Barbareschi M, Cambiaghi S, et al. Heterochromia of the scalp hair: a result of pigmentary mosaicism? J Am Acad Dermatol 2001; 45:136.
  18. Khurana A, Singal A, Pandhi D. Hypomelanosis of Ito and multiple naevoid hypertrichosis: rare cutaneous mosaicism. Australas J Dermatol 2014; 55:e29.
  19. Shimizu K, Makino T, Ueda C, et al. Detection of hypohidrosis in Japanese patients with pigmentary mosaicism. Eur J Dermatol 2013; 23:913.
  20. Treat J. Patterned pigmentation in children. Pediatr Clin North Am 2010; 57:1121.
  21. Pavone P, Praticò AD, Ruggieri M, Falsaperla R. Hypomelanosis of Ito: a round on the frequency and type of epileptic complications. Neurol Sci 2015; 36:1173.
  22. Pavone V, Signorelli SS, Praticò AD, et al. Total Hemi-overgrowth in Pigmentary Mosaicism of the (Hypomelanosis of) Ito Type: Eight Case Reports. Medicine (Baltimore) 2016; 95:e2705.
  23. Myers JN Jr, Davis L, Sheehan D, Kulharya AS. Mosaic tetrasomy 13q and phylloid hypomelanosis: a case report and review of the literature. Pediatr Dermatol 2015; 32:263.
  24. Oiso N, Tsuruta D, Imanishi H, et al. Phylloid hypermelanosis and melanocytic nevi with aggregated and disfigured melanosomes: causal relationship between phylloid pigment distribution and chromosome 13 abnormalities. Dermatology 2010; 220:169.
  25. Happle R. Phylloid hypermelanosis: an unusual form of pigmentary mosaicism. Dermatology 2010; 220:183.
  26. Küster W, König A. Hypomelanosis of Ito: no entity, but a cutaneous sign of mosaicism. Am J Med Genet 1999; 85:346.
  27. Lee HS, Chun YS, Hann SK. Nevus depigmentosus: clinical features and histopathologic characteristics in 67 patients. J Am Acad Dermatol 1999; 40:21.
  28. Mehta V, Vasanth V, Balachandran C, Mathew M. Linear and whorled nevoid hypermelanosis. Int J Dermatol 2011; 50:491.
  29. Ertam I, Turk BG, Urkmez A, et al. Linear and whorled nevoid hypermelanosis: dermatoscopic features. J Am Acad Dermatol 2009; 60:328.
  30. Di Lernia V. Linear and whorled hypermelanosis. Pediatr Dermatol 2007; 24:205.
  31. Sybert VP. Hypomelanosis of Ito: a description, not a diagnosis. J Invest Dermatol 1994; 103:141S.
  32. Taibjee SM, Hall D, Balderson D, et al. Keratinocyte cytogenetics in 10 patients with pigmentary mosaicism: identification of one case of trisomy 20 mosaicism confined to keratinocytes. Clin Exp Dermatol 2009; 34:823.
  33. Tümer Z, Møller LB. Menkes disease. Eur J Hum Genet 2010; 18:511.
  34. Fete M, Hermann J, Behrens J, Huttner KM. X-linked hypohidrotic ectodermal dysplasia (XLHED): clinical and diagnostic insights from an international patient registry. Am J Med Genet A 2014; 164A:2437.
  35. de Golian E, Echols K, Pearl H, Davis L. Linear atrophoderma of Moulin: a distinct entity? Pediatr Dermatol 2014; 31:373.
  36. Rieger E, Kofler R, Borkenstein M, et al. Melanotic macules following Blaschko's lines in McCune-Albright syndrome. Br J Dermatol 1994; 130:215.
  37. Catherine S, Lacour JP, Passeron T. Treatment of linear and whorled hypermelanosis with Q-switched laser. Dermatol Surg 2014; 40:1044.
  38. Lombillo VA, Sybert VP. Mosaicism in cutaneous pigmentation. Curr Opin Pediatr 2005; 17:494.