What are some common causes of petechiae?

Some common causes of petechiae include prolonged straining when crying, coughing or vomiting; certain medications; injuries; and infectious diseases such as meningococcemia, scarlet fever and strep throat, as listed by Mayo Clinic. Other causes of petechiae include medical conditions such as leukaemia, vasculitis and vitamin K deficiency.

Petechiae are round flat red spots under the skin that develop due to the leaking of blood from the capillaries, as reported by MedicineNet. Petechiae commonly appear in clusters and often appear similar to a rash, according to Mayo Clinic. Petechiae sometimes appear on the inner surfaces of the mouth and the eyelids.