Petechiae are tiny, flat, red spots that appear beneath the skin due to bleeding underneath the surface. These spots are red because they contain blood that has seeped into the skin. Measuring less than 3 millimeters in diameter, petechiae do not change color when pressure is applied. They can occur due to a variety of conditions, ranging from minor to severe. Common causes include local injuries, allergic reactions, certain diseases, viral infections that affect blood clotting, thrombocythemia (a low platelet count), medical treatments like chemotherapy and radiation, immune thrombocytopenic purpura (ITP), and other cancers that reduce platelet levels, as well as septicemia (bloodstream infection). Petechiae are often observed in newborns shortly after birth and can appear after intense vomiting or coughing. Medications like the anticoagulants warfarin (Coumadin), aspirin, and other similar drugs can also lead to the development of petechiae.