Mongolian blue spot

These are also relatively common in babies of Indo-Asian or Afro-Caribbean origin and occur in over 90% of children of Mongolian extraction. They consist of a blue grey patch on the skin which often occurs on the sacrum but can occur anywhere on the body. The skin surface is normal. The cause is thought to be elongated melanocyte precursor cells in the dermis. They can be mistaken as trauma from non-accidental injury, so should be documented in the notes. For most children these patches will fade as they get older, some however will persist into adulthood.