Blueness of the skin
It is typical in many newborn babies for their hands and feet to look blue. Babies who have a pale skin often show a bluish mottling of the skin all over their bodies when undressed. In both cases this is insignificant, and it disappears as the baby gets older.
Birthmarks
Port wine stains
Port wine stains are areas of skin that have a deep red coloring but are flat and otherwise normal. They are similar to the collections of red, mottled spots on the neck and eyelids, but they occur on other parts of the baby's body, are apt to be larger, deeper-colored, and more permanent. Some of them do fade, particulalrly the lighter-colored ones. There is no easy treatment for them.
Mongolian spots
Mongolian spots are blue-gray patches in the skin in dark-skinned babies. They're usually around the buttocks, and may be scattered in other areas. They almost always disappear completely in the first two years.
Salmon patches
Salmon patches are flat, pink-to-red, irregularly shaped spots on the eyelids or forehead ("angel kisses") or the nape of the neck ("stork bites". The facial spots always disappear completely. The spots on the neck may continue into adulthood.
Strawberry marks
Strawberry marks are fairly common. These are raised and are of an intense, deep-crimson color. They look very much like a piece of the outside of a shiny strawberry. They may be small at birth and later increase in size or they may not appear at all until after birth. They are apt to grow for a while and then stop.
Cavernous hemangiomas
Cavernous hemangiomas are fairly large blue-and-red marks caused by a collection of distended veins deep in the skin. Sometimes they can be removed surgically if they are disfiguring or irritated by the clothing.
Jaundice
Many newborn babies develop a yellow tinge to their skin called jaundice, due to the still immature liver. Though a little jaundice is common, occasionally the level can be high enough to worrisome. The doctor may want to watch the degree of jaundice, which he can do with a simple blood test which measures the chemical responsible for the jaundice. Giving the baby ample calories and fluid helps. On rare occasions, further measures are necessary. Jaundice is rarely a problem after the first 7-10 days of life.
Text source: Dr. Spock's Baby and Child Care -Beanjamin Spock and Michael Rothenberg