Final answer:
The abnormal blue coloration of the skin is termed cyanosis, which can be a sign of serious health conditions such as congenital heart defects resulting in "blue baby" syndrome or other systemic diseases.
Step-by-step explanation:
The abnormal condition of the skin being blue is known as cyanosis, which can occur due to several underlying health issues. For instance, when severe septal defects like tetralogy of Fallot and patent foramen ovale are present, this can lead to a "blue baby" syndrome. Despite the normal skin pigmentation, individuals with this syndrome experience an insufficient supply of oxygenated blood, especially when active, leading to the blue discoloration of the skin.
Moreover, it is important to understand that changes in skin color can be indicative of various medical conditions affecting different body systems. For example, liver disease can result in jaundice, which causes the skin to appear yellow, and Addison's disease can lead to a deep bronze color of the skin.