What Is Blaschko's Lines?

Blaschko's lines, also called the lines of Blaschko, are lines of normal cell development in the skin. These lines are invisible under normal conditions, but can become apparent as whorls, patches, streaks or lines in a linear or segmental distribution over the skin due to a mosaic skin condition.

What causes Blaschko's lines to be visible?

This rare phenomenon is referred to a genetic mosaicism. Blaschko's lines become visible, if the mutation causes, or makes the skin it effects, more susceptible to diseases that alter the pigment of the skin.

Is there a way to see blaschko lines?

To the human eye they are invisible, but they can be seen under UV light. The lines were discovered by German dermatologist Alfred Blaschko 75 years ago, Dr Bav Shergill, of the British Association of Dermatologists told MailOnline.