Having a purpura rash may mean that the patient has a low blood platelet count, according to MedlinePlus. This is called thrombocytopenic purpura. Other reasons for the rash include hemophilia and other blood clotting problems, amyloidosis, congenital cytomegalovirus or rubella syndrome and hemangioma.
The patient may also develop a purpura rash because of medications she's taking that affect her blood platelets, weakened blood vessels, vasculitis, vaginal childbirth and scurvy, according to MedlinePlus.
Thrombocytopenic purpura occurs because the low blood platelet count keeps the blood from clotting properly, and the patient is subject to internal bleeds, according to Mayo Clinic. The platelet count is normal in other types of purpura rashes, notes MedlinePlus.
Amyloidosis is a disease where a protein called amyloid builds up in the body, according to Mayo Clinic. This protein, which is abnormal, is made in the bone marrow and can attack all the tissues or organs in the body.
Congenital cytomegalovirus happens when a woman with cytomegalovirus passes her disease to her unborn baby, claims MedlinePlus. Many babies aren't born with symptoms, but a purpura rash that appears at birth is one symptom, as are an enlarged liver and spleen, jaundice, retinal inflammation and seizures.
Hemangiomas are non-cancerous clumps of blood vessels that often appear on the skin, claims Healthline. They also appear on the internal organs, especially the liver.