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Medical glossary

Petechiae

Petechiae are tiny, pinpoint red-purple spots on the skin or inside the mouth. They come from bleeding from small blood vessels.

Last updated: ~1 min read
Small red-purple pinpoint spots (petechiae) on the skin of a lower leg
Figure 1.Petechiae on the skin

01Short answer

Petechiae often signal a shortage of platelets and can be one of the first signs of leukaemia. They do not fade when pressed (the glass test). They may appear on the legs, in the mouth or on the chest. New petechiae, especially with fever, bruising or other bleeding, should be shown to a doctor straight away. In a child, petechiae with fever are an emergency.

02Simple explanation

Tiny dots.

They do not fade when pressed.

Low platelets.

Show your doctor.

03Scientific explanation

NCI: petechiae are small red or purple spots caused by bleeding under the skin.

The NCI Dictionary explains cancer terms in plain language; check the exact meaning for your situation with your doctor.

04What happens in the body?

The glass test

Press a clear glass on the spots: if they do not fade, see a doctor.

The glass test
Figure 2.The glass test — Petechiae

Urgent

Petechiae with fever.

Low platelets
Figure 3.Low platelets — Petechiae

Where you will see this word

In test results, discharge letters and conversations with your doctor. Write the word down and ask what it means.

Ask your doctor

The general meaning and the meaning of your own result can differ. The most important question is “What does this mean for me?”

05From an unfamiliar word to a clear answer: four steps

Write it down, look it up, prepare a question, ask.

Write it down — From a result or a conversation.1Write it downFrom a result or a conversation.
Look it up — Learn the plain meaning.2Look it upLearn the plain meaning.
Prepare a question — What does this mean for me?3Prepare a questionWhat does this mean for me?
Ask — Your doctor gives the personal explanation.4AskYour doctor gives the personal explanation.
UnderstandingResults feel less frightening.
ConversationA shared language with your doctor.
SafetyNot drawing conclusions alone.

06Key points at a glance

TopicIn brief
The glass testPress a clear glass on the spots: if they do not fade, see a doctor.
UrgentPetechiae with fever.
Where you will see this wordIn test results, discharge letters and conversations with your doctor. Write the word down and ask what it means.
Ask your doctorThe general meaning and the meaning of your own result can differ. The most important question is “What does this mean for me?”

07Key terms

Purpura
Larger areas of bleeding.
Ecchymosis
A bruise.
Term
A word with a precise medical meaning.
Reference range
The range a laboratory considers normal.

08Key points

  • Learn.
  • Ask your doctor.
  • Write it down.
  • Write the word down.
  • Ask what it means.

09Frequently asked questions

How do I tell them from a rash?

They do not fade when pressed; if in doubt, see a doctor.

Will they go away?

They fade once the cause is treated.

This word is in my results: should I worry?

The word itself does not mean a serious or mild condition; get the explanation from your doctor.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. How do I tell them from a rash?

  2. Will they go away?

  3. This word is in my results: should I worry?

My questions

12Sources

  1. National Cancer Institute. NCI Dictionary of Cancer Terms: petechiae
  2. National Cancer Institute. NCI Dictionary of Cancer Terms: thrombocytopenia
  3. National Cancer Institute. NCI Dictionary of Cancer Terms
  4. National Cancer Institute. Leukemia
  5. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: white blood cell
  6. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: neutrophil
  7. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: neutropenia
  8. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: bone marrow biopsy
  9. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: karyotype
  10. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: port
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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