So you woke up this morning and noticed mysterious red spots on your skin. First of all, don't panic. Second of all, don't Google it. OK, obviously you Googled it a little bit because you're here, but luckily you ended up in the right place.
What to know about petechiae
Henoch-Schonlein purpura - Better Health Channel
Capillary is the smallest type of blood vessel in the vascular system. Capillaries connect the smallest arteries with the smallest veins; most are so narrow that only one blood cell can pass along them at a time. The capillary wall is the conduit for material passing from an artery to a vein. The function of capillaries is to carry oxygen-rich blood to the tissues, to pass food substances to tissue cells, and to carry away waste products, such as carbon dioxide. Capillaritis is the name given to a harmless skin condition in which there are reddish-brown patches caused by leaky capillaries. It is also known as pigmented purpura. Purpura is a skin discoloration caused by bleeding hemorrhage under the skin.
Telangiectasia and Autoimmune Disease
Petechia refers to one of the three descriptive types hematomas differentiated by size, the other two being ecchymosis and purpura. Ecchymosis is defined as hematomas larger than 1 centimetre  and purpura as millimetres. The term is almost always used in the plural, since a single lesion is seldom noticed or significant. Petechiae on the face and conjunctiva eyes can be a sign of a death by asphyxiation , particularly when involving reduced venous return from the head such as in strangulation.