Hypomelanosis of Ito

A 6-year-old girl with mental retardation was seen for a physical examination. She was being followed by a neurologist for seizures that began in her first year of life. She had no acute health problems.

Swirls of hypopigmentation were present on her chest and abdomen, as were parallel streaks of hypopigmentation on 1 leg (Figures A and B). These cutaneous findings are typical of hypomelanosis of Ito, writes Howard Fischer, MD, of Wayne State University School of Medicine. This disorder is characterized by a decrease in or absence of basal-layer melanin granules in the affected areas.

The genetics of this condition are not well understood. Lesions are more pronounced on the ventral surface of the trunk and on the flexor surfaces of the limbs. This disease can be easily distinguished from incontinentia pigmenti, in which there is a bullous eruption that precedes the pigmentary changes.

About half of patients with hypomelanosis of Ito also have systemic manifestations. The CNS may be involved (mental retardation and convulsive disorders). There may be ocular involvement (strabismus, nystagmus, and microphthalmia) as well as skeletal and dental abnormalities. Treatment is directed at the systemic manifestations.