A congenital skin lesion characterized by irregular hypopigmented macules that coalesce to form plaques and occur particularly on the chest. It is generally present at birth or develops in the first days of life. It is more common in females. Diagnosis is confirmed by applying gentle friction to the lesion and the surrounding skin and checking that the erythema produced in the healthy skin does not appear in the hypopigmented lesion. This pale macule becomes more conspicuous when the lesion and its surroundings are rubbed. The margin of the naevus is ill-defined and consists of an archipelago of small anaemic spots. [ PMID:25864701 PMID:22483320 ]