Congenital hypertrichosis
Congenital hypertrichosis is present from birth and usually persists throughout life. There are several different names used by dermatologists to describe this disease. "Congenital hypertrichosis lanuginosa", and "congenital hypertrichosis universalis" are the most common names and they mean exactly the same thing, all over body hair growth which is long and non-pigmented. However, there is a variation called "congenital hypertrichosis terminalis". This condition involves all over body hair growth, but the hair is fully pigmented terminal hair and the condition is almost always associated with gingival hyperplasia (teeth defects). This is not the same as congenital hypertrichosis lanuginosa and there is a separate page describing this condition.
In addition to congenital hypertrichosis lanuginosa where hair develops all over the body, there are other case reports of individuals with hypertrichosis lanuginosa limited only to the face with the torso, arms, and legs being mostly unaffected. Some research reports have tried to collect these case reports together and have called the condition "ambras syndrome"
Lanugo hair is the very first hair to be made by an embryo’s hair follicles when still inside the womb. This hair can grow quite long but it is usually very fine and unpigmented. This first wave of hair growth is normally shed by the embryo at around 8 months gestation and replaced by fine vellus hair and terminal scalp hair in preparation for birth. Normally a few of the long lanugo hairs might survive through birth but are shed shortly after. However, sometimes a child can be born with most or all of the lanugo hairs still growing. This gives the appearance of the child being covered in a light colored fur. This excessively long hair all over the body persists throughout life. Congenital hypertrichosis lanuginosa is a very rare form of hypertrichosis affecting less than 1 in 1000 million children. It seems to have a genetic component with family histories of hypertrichosis being reported in relations of those affected. People described as "werewolves" or "wolfmen" for their excessive hair growth most likely have congenital hypertrichosis lanuginosa or terminalis. There is no known treatment available other than depilation.