Streak of white

A white forelock usually signifies poliosis, which is loss of pigment in hair follicles. Sometimes this is congenital, in which case the colour of the irises and hearing should be checked to exclude some rare disorders. However, closely examining the surrounding skin here shows there is loss of pigment and taken with the history of recent onset confirms a diagnosis of vitiligo, an autoimmune disease attacking pigment cells in the skin. The flexures and periocular skin should be examined with a Wood’s light for other evidence. Sometimes poliosis will follow regrowth of hair in alopecia areata; the new hair comes in grey before slowly repigmenting.