Becker’s naevus starts as a large area of more pigmented, but otherwise normal skin.
It is mostly seen on the trunk, particularly the shoulder or chest, but can also be seen on the legs or arms.
After puberty, there is an increased growth of hair that slowly becomes thicker and darker.
In some cases, the pigmentation change is absent and only the hairs are seen. The skin may feel thicker if the deeper skin muscle fibres are present in greater than normal amounts.