Petechiae (Pinpoint Bleeding Under the Skin): What Causes Them, Are They Dangerous, How a Dermatologist Tells Them Apart from Ordinary Red Spots, and the Signs That Need Urgent Care
Patients who come in about this almost always say the same thing: “I suddenly got lots of tiny red spots. They don’t itch, they don’t hurt, and I don’t know what they are.” The lack of itch is exactly why many people leave them alone. In fact, some painless red spots are so minor that nothing needs to be done, while others are the first sign of a condition that needs a blood test the same day.
This article focuses only on petechiae (bleeding spots under the skin), a subgroup that can be told apart from ordinary red spots with a simple test you can do at home in under ten seconds. If you are not sure which group your red spots belong to, read Red Spots on the Skin That Don’t Itch: Causes and Whether They Are Dangerous alongside this one.
What are petechiae?
Petechiae and purpura are red or purple marks caused by red blood cells leaking out of tiny capillaries and collecting in the layers of the skin, not by blood vessels widening.
This difference matters more than it seems, because it explains everything about how the spots behave.
Blood that has leaked out does not blanch when pressed, because it has nowhere to flow away to.
They do not itch, because they are not caused by the kind of inflammation that stimulates itch nerve endings.
They change colour over time like a bruise, because the body slowly breaks down the haemoglobin left behind.
They are not raised in the usual case. If a spot feels raised to the touch, that is a sign that needs special attention, explained below.
A simple test to tell whether it is really bleeding under the skin
Doctors call this test diascopy. You can do it at home and it takes less than ten seconds.
Find a clear drinking glass or a glass slide. If you have neither, pressing with a finger will do.
Press straight down on the red mark until the skin under the glass turns pale.
Watch the mark while you are still pressing, not after you let go.
Read the result like this:
It fades away when pressed and turns red again when released = the blood vessels are dilated, so this is not bleeding under the skin. It is usually an allergic rash, an inflammatory rash or dilated capillaries.
It stays just as red or purple when pressed = there really is bleeding under the skin. Keep reading this article.
It fades only partly = it may be an early stage with both inflammation and leaking blood, which can occur in early vasculitis. Have a doctor look at it.
One caution: if your skin is very dark, it can be hard to read the result by eye. Check in natural light and always compare with the neighbouring skin.
How do petechiae, purpura and bruises differ?
All three are bleeding under the skin. They differ in size, and size gives a fair hint about the cause.
Petechiae are smaller than 2 millimetres, about the size of a pinhead, and usually appear as a cluster of many spots at once. This group is the most closely linked to platelets and to pressure in the blood vessels.
Purpura measures 2 millimetres to 1 centimetre. If it feels raised to the touch, it is called palpable purpura, which points fairly clearly toward vasculitis.
Ecchymosis, or a bruise, is larger than 1 centimetre. It usually comes from a knock, fragile vessel walls or a blood clotting disorder.
If you have both many petechiae and large bruises without any knock, that combination calls for a blood test, not waiting and watching.
Why petechiae usually do not itch
This question is asked very often, and the answer genuinely helps in telling conditions apart.
Itch comes from inflammatory mediators such as histamine stimulating C-fibre nerve endings in the epidermis and upper dermis. Petechiae, however, are red blood cells that have simply leaked into the tissue, a physical process that does not release enough of those mediators, so patients feel nothing at all.
The exception to know about is the group that does involve inflammation, namely vasculitis and a group called capillaritis or Schamberg’s disease, which may itch mildly to moderately. So “bleeding spots that also itch” does not mean the diagnosis is wrong. It means the spots probably belong to an inflammatory group, which needs more evaluation than the non-itchy group.
Cause group 1: temporary rise in pressure inside the blood vessels
This is the most common and least dangerous group. It happens when pressure in the veins suddenly surges and tiny capillaries burst.
Severe vomiting or repeated hard coughing, which mainly produces petechiae on the face, around the eyes and on the neck.
Pushing during childbirth, lifting heavy objects or straining during a bowel movement.
A blood-draw tourniquet, a belt, a bag strap or tight socks, which produce petechiae in a line along the edge of the constriction.
Vigorous acupressure massage, cupping or skin scraping.
The clues for this group are a clear history, spots limited to the area that took the pressure, no increase in number afterwards, and no whole-body symptoms such as fever, fatigue or bleeding elsewhere.
Cause group 2: fragile blood vessel walls
In this group the platelets are normal, but the vessel walls themselves and the surrounding tissue that supports them have weakened.
Bleeding spots in older adults (senile purpura) are seen mostly on the backs of the hands and the forearms. They result from the collagen that supports the vessels declining with age and from accumulated sun exposure. The marks are usually dark purple with sharp edges and heal more slowly than ordinary bruises. They are not dangerous, but they show that the skin has been damaged by the sun for a long time.
Long-term steroid use, both creams used continuously beyond what is necessary and oral steroids, thins the skin and makes the vessels fragile.
Vitamin C deficiency is uncommon today but is still seen in people with a very limited diet. The characteristic findings are bleeding spots around hair follicles together with corkscrew-shaped hairs and swollen, bleeding gums.
Inherited connective tissue disorders, such as the Ehlers-Danlos group, which usually come with loose joints and abnormally stretchy skin.
Cause group 3: low or poorly working platelets
This is the group doctors take most seriously when they see petechiae spread across the body, because platelets are the first line of defence in plugging leaks in tiny capillaries.
Possible causes
Immune thrombocytopenia (ITP), in which the body makes antibodies that destroy its own platelets. It often starts with petechiae on both legs and then spreads upward.
Dengue fever, which must always be considered in Thailand when fever occurs together with bleeding spots, especially in the rainy season. The spots usually appear on day 3 to 5 of the fever.
Drugs that suppress the bone marrow or destroy platelets, including chemotherapy and some medicines that trigger the immune system.
Diseases of the bone marrow itself, such as leukaemia and aplastic anaemia, which usually come with paleness, unusual fatigue, enlarged lymph nodes or frequent infections.
Chronic liver disease and an enlarged spleen, which cause platelets to be trapped and destroyed more.
The key clue for this group is bleeding from the mucous membranes as well: bleeding gums, more frequent nosebleeds, unusually heavy periods or bleeding spots inside the mouth. If any one of these occurs together with petechiae, a complete blood count should be done without waiting.
Cause group 4: vasculitis
Vasculitis is a condition in which the walls of small blood vessels are attacked by the immune system until they leak. The feature that sets it apart from the other groups is that the spots feel raised to the touch, called palpable purpura.
They usually appear densely on both legs and the ankles, because blood pressure in the lower body is higher.
There may also be joint pain, abdominal pain or blood in the urine.
In children there is a particular pattern called Henoch-Schonlein purpura, which often comes with abdominal pain and joint pain and requires monitoring of kidney function.
Common triggers are an infection one to two weeks beforehand, certain medicines and autoimmune diseases.
In this group a skin biopsy is the most useful, because it confirms the diagnosis and identifies the type of vessel inflammation.
Cause group 5: severe infection
This is the group that turns bleeding spots into an emergency.
Bloodstream infection with meningococcus. Petechiae appear very quickly and spread within hours, together with high fever, severe headache, a stiff neck and drowsiness. This is a medical emergency.
Severe generalised sepsis, to the point of abnormal clotting throughout the body.
Dengue and other viruses that lower platelets, which occur seasonally in Thailand.
Infective endocarditis, which may cause bleeding spots on the nails, palms and soles together with a prolonged fever.
A simple rule to remember: fever plus rapidly increasing bleeding spots means going to the hospital immediately, not booking an appointment for next week.
Medicines and supplements that commonly cause petechiae
This topic is rarely discussed in Thai-language articles, yet it is the easiest cause to fix.
Anticoagulants and antiplatelet drugs, such as aspirin and warfarin.
NSAID painkillers taken continuously, which interfere with platelet function.
Steroids, both creams used continuously for a long time and oral forms.
Some drugs that trigger the immune system to destroy platelets, such as certain antibiotics, anticonvulsants and some diuretics.
Supplements and herbs with antiplatelet effects, such as high-dose fish oil, concentrated garlic extract, ginkgo and high-dose turmeric, especially when taken together with antiplatelet drugs.
When you see the doctor, please bring photos of the labels of every medicine and supplement you take, including items you bought yourself and anything started within the last three months. This information can genuinely change how you are investigated.
What spots on the legs mean
The legs are where bleeding spots are most often found, because gravity makes the pressure in the lower capillaries higher than elsewhere. Spots therefore tend to start here first, whatever the cause.
What to distinguish when they appear on the legs
Raised to the touch: think of vasculitis first.
Flat, spread over both sides and increasing quickly: think of low platelets.
Reddish brown like ground pepper, coming and going on the shins: this is usually capillaritis, which is not dangerous but takes months to clear.
Swollen legs, darkened skin around the ankles, varicose veins: think of chronic venous insufficiency, a common cause in people who stand for long periods.
What spots on the arms mean
Bleeding spots on the arms have a clearly different context from those on the legs, because blood pressure here is not high, so spots appearing on their own mean more.
The forearms and backs of the hands in older adults: usually bleeding spots from age-related thin skin, which are not dangerous.
A band of spots along where something was tied: for example after a blood draw or blood pressure measurement. This is normal and clears on its own in 1 to 2 weeks.
Spread across both arms with no history of tight binding or knocks: this is a pattern that calls for a blood test, especially if it has spread up from the legs.
Spots on the upper arms together with several bruises of different ages: both blood clotting and the patient’s safety circumstances should be assessed.
What spots on the face, around the eyes and on the neck mean
This location has a fairly specific answer, and it often reassures patients straight away.
Bleeding spots above the level of the heart, especially around the eye sockets and eyelids, are almost always caused by a sudden surge of venous pressure from vomiting, hard coughing, straining or intense crying. The typical features are:
They appear immediately after the event and rarely increase afterwards.
They are only above the collarbone, with none on the trunk or legs.
There is no fever and no bleeding elsewhere.
They clear on their own in 1 to 2 weeks.
But if bleeding spots on the face appear without a triggering event, or are also present on the trunk and legs, treat them as being in the group that needs a blood test.
Just one spot: is it dangerous?
In general, a single isolated bleeding spot that does not increase in number carries very low risk. The most common causes are a light knock you do not remember, hard scratching, or an insect bite that left a small bleed.
What you should do is photograph it with a coin or ruler beside it for size comparison, then watch it for another 2 weeks. See a doctor if any one of the following applies.
A new spot appears the next day.
The original spot gets bigger instead of fading.
The original spot stays in the same place for more than 3 weeks without changing colour.
There is fever, fatigue or bleeding elsewhere.
Skin conditions that look similar but are not petechiae
Many people worry more than necessary because they confuse petechiae with these marks, which blanch when pressed or have distinctive features that set them apart.
Cherry angioma: a bright red, smooth, round spot, slightly raised, found mostly on the trunk in people aged 30 and over. It has been there for a long time and adds one spot at a time slowly over many years. It is not bleeding.
Spider naevus: a red dot in the centre with branches spreading around it. When you press the centre, the branches fade completely.
Capillaritis or Schamberg’s disease: reddish brown like sprinkled ground pepper, usually on the shins. It is not dangerous but fades slowly over several months.
Early hives, which blanch when pressed and itch noticeably.
Marks from procedures such as suction or certain lasers, which have a clear history and clear on schedule.
If you cannot tell by eye, dermoscopy at a dermatology clinic takes only a few minutes and gives a fairly clear answer.
How many days do petechiae take to heal?
This is something many people search for, but almost no article gives a real timeline.
Petechiae change colour as haemoglobin breaks down; they do not simply fade.
Days 1 to 3: bright red to dark red.
Days 3 to 7: turns dark purple or greyish blue.
Days 7 to 12: turns greenish brown or yellow.
Weeks 2 to 3: fades until it disappears. Some people are left with a faint dark mark for several more weeks.
The key point is that at every stage the mark still does not blanch when pressed, and at no stage should it get bigger.
If a mark stays in the same place for more than 3 weeks without going through this colour sequence, or new spots keep appearing to replace old ones so that it seems never to heal, that is not slow healing but a process that is still going on, and it should be examined.
Warning signs that need the hospital immediately
If any one of the following is present, do not wait for an appointment or watch and wait.
Fever together with bleeding spots that increase rapidly within a few hours.
Severe headache, stiff neck, confusion or drowsiness.
Spots spreading into large purple-black patches.
Bleeding from the mucous membranes: bleeding gums, a nosebleed that is hard to stop, vomiting or passing blood, unusually heavy periods.
Bleeding spots in a child with a fever, especially a young child who is unusually fretful or drowsy.
Bleeding spots in someone receiving chemotherapy or with a weakened immune system.
Raised bleeding spots together with joint pain, abdominal pain or dark urine.
What the doctor will check
Many people hesitate to see a doctor because they do not know what to expect. Knowing in advance makes the decision easier.
The history will focus on duration, the order of the locations affected, fever, every medicine and supplement, a preceding infection, a family history of abnormal bleeding and other whole-body symptoms.
The physical examination will test blanching on pressure, feel whether the spots are raised, examine the mouth and mucous membranes, feel the lymph nodes and spleen, and look for signs of liver disease.
Laboratory tests that are often ordered
Complete blood count (CBC) to look at platelet count, white cells and anaemia. It is always the first test.
Blood smear to confirm whether platelets are truly low or falsely clumped, and to look for abnormally shaped blood cells.
Clotting tests, PT and aPTT, when a clotting factor problem is suspected.
Dengue testing when there is fever in a high-risk season.
Liver and kidney function and a urine test, especially when vasculitis is suspected.
Skin biopsy in cases where the spots are raised or chronic with no known cause.
Most of the time, the first set of tests takes little time and rules out the dangerous groups on the same day.
How to look after yourself while waiting to see the doctor
Take a photo every day in the same light, with a coin beside the spots for size. This set of photos is worth more to the doctor than you might think, because it shows the rate of increase.
Write down every medicine and supplement, including those you bought yourself and any started within the last three months.
Avoid vigorous acupressure, cupping and skin scraping on the affected area.
Avoid over-the-counter NSAID painkillers and aspirin until the cause is known. If you take a regular medicine prescribed by a doctor, do not stop it on your own; consult the doctor first.
Take your temperature twice a day and go to the hospital immediately if there is a fever together with spots that are increasing.
There is no need to buy a cream, because bleeding spots do not respond to topical medicines, and putting on a steroid cream yourself may thin the skin and make things worse.
Frequently asked questions
What causes petechiae?
They are caused by red blood cells leaking out of tiny capillaries and collecting in the layers of the skin. The causes fall into five main groups: a temporary rise in vessel pressure from coughing, vomiting or tight items; fragile vessel walls from age, sun or steroids; low or poorly working platelets; vasculitis; and severe infection. The first group is the most common and not dangerous, while the last three groups need a blood test to tell apart.
Are petechiae dangerous?
Most are not dangerous and clear on their own, but they become urgent when any one of the following is also present: fever with spots increasing rapidly within a few hours; severe headache or a stiff neck; bleeding gums or a nosebleed that is hard to stop; unusually heavy periods; marked paleness or fatigue; or raised spots together with joint and abdominal pain. In these cases go to the hospital immediately rather than waiting for an appointment.
How many days do petechiae take to heal?
They generally take 2 to 3 weeks, and change colour in sequence: bright red in the first three days, purple or blue in the first week, greenish brown or yellow in the second week, and then fade away. At every stage the mark still does not blanch when pressed. If after 3 weeks it is still in the same place without going through this colour sequence, or new spots keep appearing to replace it, see a doctor to look for a cause that is still active.
How do petechiae differ from ordinary red spots?
They can be told apart with a pressure test. Press a clear glass or a finger onto the mark and watch while still pressing. If the mark fades and turns red again on release, the vessels are dilated, as in an allergic rash or a cherry angioma. If the mark stays just as red or purple while pressed, there really is bleeding under the skin. In addition, petechiae usually do not itch, are not raised in the usual case, and change colour over time like a bruise.
I have bleeding spots on my legs but no itch. What should I do?
The legs are the most common location because blood pressure in the lower body is higher. What needs assessing is whether the spots are raised to the touch, whether they are on both sides or one, and how fast they are increasing. If raised, think of vasculitis. If flat, spread on both sides and increasing quickly, think of low platelets. Either pattern should see a doctor within a few days. Reddish brown, pepper-like marks on the shins that come and go are usually a harmless condition that clears slowly.
What medicine cures petechiae?
No medicine treats petechiae themselves, because the marks are only a sign. Treatment is aimed at the cause. If it is caused by a medicine or supplement, an adjustment by a doctor is the answer. If it is caused by immune thrombocytopenia, immunosuppressive drugs are used according to clinical guidelines. If it is caused by vasculitis, the inflammation must be treated and the trigger sought. If it is caused by infection, that infection must be treated. Buying creams or vitamins yourself therefore does not help, and may cause a delay that comes too late when the cause is dangerous.
Written by Dr. Patara Voravutinon, Dermatologist · Last reviewed September 3, 2026
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