What Causes Purple Spots (Purpura) on Skin?

Have you ever seen purple spots on your skin and wondered what causes them?

Purpura is a term used to describe this condition, which can occur for a variety of reasons.

From an injury to an underlying medical condition, there are many potential causes of purple spots on the skin.

While purpura may seem harmless, it can sometimes be a sign of a more serious condition.

If you have any concerns about the purple spots on your skin, it’s important to speak with a healthcare professional or dermatologist.

In this article, we’ll explore the different causes of purpura and what you can do to treat it.

What is Purpura?

Purpura is a dark spot or patch on the skin that does not fade when you press on it. They appear purple in color on light skin and dark brown on black or darker skin.

Leaks in small blood vessels cause these spots. They can show up on the skin and mucous membranes, which include the lining of your mouth.

Causes of Purple Spots on Skin

There are many potential causes of purple spots on the skin. These include:

Non-thrombocytopenic Purpura

Blood clotting disorders can cause purpura.

Platelets are pieces of large cells that help the blood to clot. A person with purpura may have normal platelet counts or low platelet count. 

In the case of non-thrombocytopenic purpura, the platelet level is within the normal range.

One type of non-thrombocytopenic purpura which can occur in young children is Henoch-Schönlein purpura.

This type of purpura frequently appear before a respiratory infection and is often accompanied by abdominal pain and a leg rashes.

Symptoms often go away on their own. However, some people with Henoch-Schönlein purpura suffer dangerous inflammation that leads to kidney problems.

The following could cause nonthrombocytopenic purpura:

• Disorders that affect blood clotting
• Certain congenital disorders present at or before birth, such as telangiectasia (fragile skin and connective tissue) or Ehlers-Danlos syndrome
• Certain medications, including steroids and those that affect platelet function
• Weak blood vessels
• Inflammation in the blood vessels
• Scurvy, or a severe lack of vitamin C

Thrombocytopenic Purpura

A person with thrombocytopenic purpura has low platelet counts.

The following could cause thrombocytopenic purpura:

• Medications that prevent platelets from forming or that interfere with normal clotting
• Drugs that cause the body to launch an immune reaction against platelets
• Recent blood transfusions
• Immune disorders such as idiopathic thrombocytopenic purpura
• An infection in the bloodstream
• Infection by HIV or Hepatitis C, or some viral infections (Epstein-Barr, rubella, cytomegalovirus)
• Rocky Mountain spotted fever (from a tick bite)
• Systemic lupus erythematosus (SLE) and other autoimmune diseases

Idiopathic Thrombocytopenic Purpura (ITP)

Idiopathic thrombocytopenic purpura (ITP) occurs when the body attacks its own platelets, increasing the risk of bleeding and purpuric rashes.

The normal platelet count is in the range of 150,000 to 450,000. With ITP, the platelet count is less than 100,000.

Diseases that impair bone marrow function may restrict the body’s ability to make platelets and attack bone marrow.

Examples of such diseases include:

• Leukemia
• Aplastic anemia
• Myeloma
• Bone marrow tumors

Diagnosis

The spots caused by purpura are fairly easy to tell apart from other rashes. Also, purpura may not be accompanied by itching.

Finding the underlying cause of the purpura can be tricky, which is why healthcare professionals often ask questions such as:

• Do you have any other symptoms?
• Does anyone else in the home have the same symptoms?
• How long have you had the rash?
• Have you had this rash before?
• Do you take any medications?
• Are there any other medical problems?

A Complete Blood Count (CBC), a blood test, can help diagnose purpura and its cause.

A CBC will reveal whether the patient has low platelets and whether there is an underlying infection.

If your healthcare professional suspects ITP, they may order additional testing.

Certain clinical situations may call for bone marrow testing. A skin biopsy can also provide important information, particularly when a healthcare professional is unable to find an underlying cause for the purpura.

If there is a  suspicion of Henoch-Schönlein purpura, urine tests can assess kidney function by testing for protein and blood in the urine.

Your healthcare professional may also perform other tests based on the patient’s symptoms and the suspected diagnosis.

Treatment

Not all cases of purpura require immediate treatment and medical help.

However, some underlying causes of purpura can be life-threatening.

Treatment for Henoch-Schönlein purpura

Healthcare professionals may recommend NSAIDs to reduce inflammation and pain in some cases.

However, people with gastrointestinal or kidney issues should avoid these medications.

Healthcare professionals may prescribe drugs to suppress the immune system if kidney damage is severe. Treatments vary depending on a person’s specific needs.

Treatment for Solar Purpura

Over time, reductions in subcutaneous fat and connective tissue and long-term sun exposure can lead to increased bruising of mature skin as the result of minor trauma.

This is known as actinic purpura. Other names for this include solar purpura, senile purpura, traumatic purpura, and Bateman’s disease.

This variation of purpura is common in older adults, and the risk increases with age,  affecting 1 in 4 aged 90-100 years. No treatment is necessary for this type of purpura.

However, a person can speak with their healthcare professional or dermatologist about options for reducing or improving the appearance of these marks.

Treatment for ITP

ITP symptoms range from mild to severe, and some patients require no treatment at all.

Those who do may benefit from drugs designed to boost platelet count or, in rare cases, the removal of the spleen.

Lifestyle treatments can also help since drugs such as aspirin prevent platelets from aggregating and clotting.

Some new medications are also available. Hematologists who can offer a specific treatment plan can help treat difficult-to-treat ITP.

Treatment for other forms of purpura

Other forms of purpura are treated with a focus on tackling the underlying cause rather than the skin manifestation. Some of these treatment options include:

Corticosteroids

Corticosteroids can help increase platelet count by reducing the activity of the immune system.

The drug will be used for 2-6 weeks to ensure that the platelets return to a normal level. The side effects of using corticosteroids for an extended period of time include cataracts, bone loss, and weight gain.

Intravenous immune globulin (IV-IgG)

If your type of purpura is causing severe a very low platelet count to the point of being dangerous, your healthcare professional may give you an intravenous medication called intravenous immunoglobulin (IV-IgG).

They may also give you IV-IgG if you need to increase your platelet count rapidly before surgery.

While this treatment is generally effective in increasing your platelet count, the effect is usually only for the short term. It can also cause side effects such as headache, nausea, and fever.

Splenectomy

If medications aren’t effective in treating thrombocytopenic purpura, your healthcare professional may recommend a splenectomy. Removing the spleen is a fast way of increasing your platelet count.

This is because the spleen is the main body part responsible for eliminating platelets. However, splenectomies aren’t effective for everyone.

The surgery also comes with risks, such as a permanently increased risk of infection. 

Additionally, in emergency cases where purpura causes extreme bleeding, hospitals will perform transfusions of platelet concentrates, corticosteroids, and immunoglobulin.

Other drug therapies

Drugs that can be used to treat low platelet count in people with chronic immune (idiopathic) thrombocytopenic purpura (ITP) are romiplostim (Nplate) and eltrombopag (Promacta).

These medications cause bone marrow to produce more platelets, which reduces the risk of bruising and bleeding. Potential side effects include:

• Headaches
• Dizziness
• Nausea
• Joint or muscle pain
• Vomiting
• Increased risk of blood clots
• Acute respiratory distress syndrome
• Pregnancy

Biologic therapy, such as the drug rituximab (Rituxan), can help decrease the immune system response.

It’s mostly used to treat patients with severe thrombocytopenic purpura and patients for whom corticosteroid treatment isn’t effective.

Side effects may include:

• Low blood pressure
• Sore throat
• Rash
• Fever

When to Seek Medical Attention

You should seek medical assistance from a healthcare professional if you notice purpura or any blood spots, patches, or skin discoloration.

Purpura can be a sign of a severe disease or underlying condition.

For example, if purpura is related to a blood clotting disorder or low platelet levels, it can put your life at risk. In other cases, purpura isn’t serious and resolves with minimal treatment.

Unless you get tested and diagnosed by your healthcare professional, there isn’t a way to be sure.

How K Health Can Help

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