What causes hypertrichosis?
The cause of hypertrichosis is unknown. Congenital hypertrichosis is believed to be a genetic disorder that is inherited or occurs as a result of spontaneous mutation. Acquired hypertrichosis lanuginosa sometimes occurs in people who at a later stage are diagnosed with a cancer of some form. This hair growth, also known as malignant down, is often confined to the face with long fine silky hair noticeable on the nose and eyelids, sites that are normally hairless. It is not known why a cancer causes this excessive hair growth.
