How are birth marks made? – Darmstadtium Zone

Question: How are birth marks made?
- Keywords:
  human body
Asked by anon-225189 to Simon, Paul, Nawapat, Natalie, Katy on 21 Nov 2019.
- Paul Laurance-Young answered on 21 Nov 2019:
  
  A birthmark is an area of skin, typically on the face, where a greater number of blood vessels have collected that remain wide open (termed a haemangioma – but not a haemangioma… welcome to biology, it’s so confusing sometimes!)
  This gives it a characteristic red colour.

Question: How are birth marks made?