Affected Populations
In earlier reports, hypomelanosis of Ito affected women more often than men by a ratio of 2.5:1. More recent, larger studies suggest that the difference may not be as large. The incidence of hypomelanosis of Ito is estimated to be 1 in 8,000-10,000 people in the general population. The symptoms usually become apparent during the first or second year of life. Hypomelanosis of Ito was first described in the medical literature in 1952.