Purpura: What You Need to Know

Medically Reviewed By Emelia Arquilla, DO
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Purpura occurs when blood pools under the skin because of small blood vessels bursting. These spots are typically 4 millimeters (mm) or more in diameter and can appear purple, red, or brownish-yellow. Common causes of purpura include blood clotting disorders, immune disorders, and certain medications. Treatment for purpura typically involves treating the underlying cause. You may need to stop taking medications that affect the blood’s ability to clot.

Read on to learn more about the types, causes, and treatments for purpura.

What are the different types of purpura?

A doctor checks a person's skin
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Doctors typically split purpura into two main types: thrombocytopenic and nonthrombocytopenic.

Thrombocytopenic purpura

“Thrombocytopenia” means low blood platelet counts, and thrombocytopenic purpura results from a deficiency of platelets in the blood. Platelets are cells that help your blood clot.

People with thrombocytopenia may experience excessive or lengthy bleeding from small injuries, easy bruising, and fatigue.

Nonthrombocytopenic purpura

Nonthrombocytopenic purpura is not associated with low blood platelet counts. Congenital disorders, certain types of vasculitis, and vitamin C deficiency can all contribute to this type of purpura.

Solar or senile purpura is a type of nonthrombocytopenic purpura. The spots occur on aging or sun-damaged skin.

What are the causes of purpura?

Common causes of thrombocytopenic purpura include:

  • medications that interfere with clotting by reducing your platelet count
  • Rocky Mountain spotted fever
  • immune disorders, such as immune thrombocytopenia or idiopathic thrombocytopenic purpura
  • lupus
  • serious infections, such as HIV

Nonthrombocytopenic purpura may result from these conditions:

  • Henoch-Schönlein purpura (HSP), a condition that occurs when small blood vessels called capillaries become inflamed
  • congenital disorders such as Ehlers-Danlos syndrome
  • blood clotting disorders
  • vitamin C deficiency
  • age-related deterioration of the blood vessels

What does purpura look like?

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Purpura are spots on the skin caused by bleeding from small blood vessels.

Photography courtesy of Hektor/Wikimedia

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Solar purpura, also known as senile purpura, typically occurs in aging or sun-damaged skin.

Photography by DermNet New Zealand

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Henoch-Schönlein purpura can cause large red or purple patches on the skin.

Photography courtesy of Mohammad2018/Wikimedia

Purpura can look purple, red, or brownish-yellow on fair skin. On darker skin tones, they tend to appear dark brown or black. They are typically 4 mm or more across. Spots that are less than 4 mm in diameter are known as petechiae.

Purpura spots are typically non-blanching, meaning their coloration does not change when pressed. The spots may also be tender.

Purpura typically occurs on the skin but can also occur in your body’s mucous membranes.

What other symptoms might occur with purpura?

If the purpura is associated with thrombocytopenia, other symptoms may occur:

If your purpura is nonthrombocytopenic, you may also experience other symptoms, including:

How do doctors diagnose purpura?

To diagnose the underlying cause of purpura, doctors will typically begin by conducting a physical examination and asking you about your medical history.

Blood tests can measure your platelet levels, helping doctors determine if your purpura is thrombocytopenic or nonthrombocytopenic. Doctors may also perform a blood smear, which involves putting a sample of your blood on a slide to look at the platelets under a microscope.

Your doctors can also perform bone marrow tests to check if your bone marrow is producing typical amounts of cells. These tests include:

  • Aspiration: Aspiration involves taking a sample of your bone marrow fluid through a needle.
  • Biopsy: This procedure typically occurs at the same time as aspiration. In this biopsy, doctors may take a sample of bone marrow tissue for analysis.

A skin biopsy may also be necessary if your platelet levels are regular.

What are the treatments for purpura?

Treatment for purpura involves addressing the underlying cause. Common treatments include:

  • Medications: Steroids can help increase your platelet levels. If an immune system disorder is causing purpura, medications such as rituximab can keep your immune system from interfering with your platelets.
  • Transfusions: Receiving an IV transfusion of healthy blood or platelets can help restore platelet counts.
  • Splenectomy: Because the spleen stores platelets, surgically removing it may help increase your blood’s platelet counts.

Other treatments may also be necessary. For example, if you have Henoch-Schönlein purpura, your doctor may recommend hemodialysis. This procedure filters out waste products from the blood when your kidneys cannot do so.

If you are already taking medications that affect your blood’s ability to clot, your doctor may recommend discontinuing those medications.

What is the outlook for people with purpura?

The outlook for people with purpura depends on the underlying cause. Some cases of purpura will resolve on their own without treatment.

Severe thrombocytopenia can lead to excessive internal bleeding. If the bleeding occurs in the brain, it can be fatal.

If you think you have purpura, it is important to talk with your doctor as soon as possible. They can diagnose the underlying condition and start any necessary treatment.

Can you prevent purpura?

Preventing purpura involves preventing or treating the underlying causes. Many conditions that cause purpura are unavoidable but are treatable with medications.

Following your doctor’s treatment plan for any conditions you may have is the best way to treat and prevent purpura.

Frequently asked questions

Here are some commonly asked questions about purpura. Dr. E. Mimi Arquilla, a doctor of osteopathic medicine, has medically reviewed the answers.

Can purpura go away?

While some cases of purpura go away on their own, treating the underlying condition will help your purpura clear up. For example, if you have low platelet counts, taking medication to boost your platelet counts can help prevent blood pooling under your skin.

Is purpura a bruise?

Purpura looks like a bruise, but they have different causes. Bruises occur due to physical trauma or injury. Purpura, however, results from blood leaking under the skin due to blood vessel deterioration, blood clotting disorders, or medications that affect platelet counts.

Summary

Purpura is a rash of spots when blood pools under the skin. The spots can be red, purple, or brownish-yellow and are typically more than 4 mm in diameter.

Purpura can result from low blood platelet counts, or they may result from conditions with typical platelet levels. Common causes of purpura include medications that affect blood clotting, Rocky Mountain spotted fever, idiopathic thrombocytopenic purpura, and infections.

Doctors typically use blood tests, bone marrow tests, or skin biopsies to diagnose the underlying cause of purpura. Treatments may include medications, transfusions, or surgery.

If you think you have purpura, talk with your doctor to discuss diagnosis and treatment options.

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Medical Reviewer: Emelia Arquilla, DO
Last Review Date: 2022 May 23
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