Hypomelanosis of Ito

Updated: Apr 18, 2016
  • Author: Manuel Valdebran, MD; Chief Editor: Dirk M Elston, MD  more...
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Overview

Background

Hypomelanosis of Ito is a pigmentary mosaicism characterized by hypopigmentation in the forms of streaks and whorls running along the lines of Blaschko. This condition is seen as an isolated cutaneous finding or associated with musculoskeletal and neurological conditions. Ophthalmic, hair, and dental abnormalities have also been described. [1, 2] See the image below.

Hypomelanosis of Ito on the torso. Hypomelanosis of Ito on the torso.

 

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Pathophysiology

The affected areas seen in hypomelanosis of Ito result from a clone of skin cells with reduced capacity to produce pigment. Structural or numerical chromosomal aberrations present in these clones of cells have been linked with this entity. Around 90% of these chromosomal aberrations are present in the locations of genes involved in pigmentation. [3] Associations of different numerical chromosomal disorders can be found in the literature, such as trisomy of chromosome 2, 13,14, 18, or 20 mosaicisms. [4, 5]

Extracutaneous manifestations might be due to the presence of different genetic defects.

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Epidemiology

Frequency

Hypomelanosis of Ito is rare.

Race

No clear racial predilection is reported for hypomelanosis of Ito.

Sex

Hypomelanosis of Ito is 1.5-2.5 times more common in women than in men.

Age

Hypomelanosis of Ito is present at birth, and patients usually undergo examination in their first or second years of life. Approximately 75% of patients with hypomelanosis of Ito seek care by the time they are aged 2 years. One fourth of patients seek care after they are aged 2 years, before they are aged 5 years. Skin lesions may become pigmented over time and blend well with normally pigmented skin.

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Prognosis

The prognosis is determined by the associated abnormalities. The prognosis is excellent for the cutaneous findings. Death is rare. Morbidity depends on severity of the associated abnormality such as seizures.

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Patient Education

Genetic counseling may be recommended. However, the risk of hypomelanosis of Ito transmission is considered low, except when X-linked mutations are present in female patients.

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