Petechiae are pinpoint-sized hemorrhages of small capillaries in the skin or mucous membranes.
What is going on in the body?
Petechiae result from tiny areas of superficial bleeding into the skin. They appear as round, pinpoint-sized dots that are not raised. The color varies from red to blue or purple as they age and gradually disappear. Petechiae commonly appear on the lower legs, but may be distributed all over the body.
What are the causes and risks of the disease?
There are many possible causes of petechiae. Common causes include:
injury or trauma
allergic reactions to medications
autoimmune disorders, which are conditions in which the person's body creates antibodies to its own tissues for unknown reasons
liver disorders, such as cirrhosis
infections, such as mononucleosis and endocarditis
bone marrow disorders, such as leukemia
thrombocytopenia, a deficiency of platelets
nutritional deficiencies, such as a deficiency in vitamins C, K, or B12, or folic acid
medications, such as blood thinners or aspirin therapy
recent blood transfusions
medical treatment, such as radiation therapy and chemotherapy for cancer
sepsis, or blood infection
violent vomiting or coughing
What can be done to prevent the disease?
It is not always possible to avoid petechiae. Avoiding trauma will help prevent petechiae caused by injury. If allergy to a medication is the cause, avoiding the medication will help prevent the condition.
How is the disease diagnosed?
Diagnosis of petechiae begins with the history and physical exam. Blood tests are usually done, including:
bleeding time, or the amount of time it takes for the blood to clot
tests that measure clotting abilities, such as a prothrombin time or partial thromboplastin time
complete blood count, or CBC
platelet count. Platelets are blood cells that aid in blood clotting. If a person has too few of them in the blood, the person may be more likely develop petechiae. A bone marrow biopsy may be done in some cases.
Other tests may also be ordered, depending on the medical history and physical findings.
Long Term Effects
What are the long-term effects of the disease?
The long-term effects of petechiae depend on the cause. For example, petechiae caused by injury will usually fade in time, and cause no long-term effects. When the cause is allergy to a medication, stopping the medication should end the condition. A person who has a severe infection with petechiae may be very ill. Petechiae may also occur in association with other life-threatening conditions.
What are the risks to others?
Petechiae are not contagious and pose no risk to others. If the cause of petechiae is an infection, such as mononucleosis or meningitis, the infection itself may be contagious.
What are the treatments for the disease?
Treatment is directed at the underlying cause of the petechiae. For example, someone with petechiae caused by an infection is given antibiotics. If petechiae are caused by allergy to a medication, the medication may need to be stopped. A person with petechiae due to a low platelet count may need a transfusion of platelets or other blood factors. A person with leukemia or cancer may need surgery, chemotherapy, or radiation therapy. Petechiae caused by injury need no treatment. Applying an ice pack off and on for 24 hours after the injury may reduce further petechiae. The petechiae will fade in time.
What are the side effects of the treatments?
All medications have possible side effects. Antibiotics can cause stomach upset, and sometimes an allergic reaction. Blood transfusions may cause allergic reactions or infections. Surgery can be complicated by infection, bleeding, or an allergic reaction to the anesthetic.
What happens after treatment for the disease?
Most petechiae will disappear when the cause is identified and treated.
How is the disease monitored?
Blood tests may be done to see if the platelet count is back to normal. If petechiae worsen, monitoring by a healthcare professional may be necessary. Any new or worsening symptoms should be reported to the healthcare professional.
Current Medical Diagnosis and Treatment, Tierney, 2000
The Merck Manual of Medical Information, 1997
Harrison's Principles of Internal Medicine, Fauci et al, 1998