Petechiae are tiny, flat spots that appear when capillaries (the smallest blood vessels in your skin) break and leak a small amount of blood into the surrounding tissue. Each spot is only 1 to 2 millimeters across, roughly the size of a pinpoint. They don’t fade when you press on them, which is the key feature that distinguishes them from ordinary rashes. The causes range from completely harmless physical strain to conditions that need prompt medical attention, and the difference usually comes down to where the spots are, how many you have, and what other symptoms accompany them.
The Most Common Cause: Physical Strain
If the spots are limited to your face, neck, or upper chest, the most likely explanation is that you strained hard enough to temporarily spike blood pressure in those small vessels. Prolonged or forceful coughing, vomiting, heavy lifting, or even giving birth can do this. The sudden pressure pushes blood through fragile capillary walls, leaving a scatter of pinpoint dots in the areas above your heart where pressure builds the most.
These strain-related petechiae are harmless. They typically fade on their own within a few days as your body reabsorbs the leaked blood. No treatment is needed, and the spots don’t signal an underlying problem. You can usually identify them by their location (concentrated around the face, eyes, or neck) and by the fact that you can remember a specific episode of straining.
Medications That Affect Clotting
Blood thinners, aspirin, and common over-the-counter anti-inflammatory painkillers all reduce your blood’s ability to clot. When you take these regularly, even minor bumps or pressure on the skin can cause capillaries to leak without sealing quickly. The result is petechiae or easy bruising that seems to appear without an obvious injury. If you’ve recently started a new medication and notice spots appearing, that’s worth mentioning to your prescribing doctor, though it doesn’t necessarily mean you need to stop the drug.
Low Platelet Count
Platelets are the tiny blood cells responsible for plugging leaks in your vessel walls. When your platelet count drops low enough, capillaries can bleed spontaneously. One of the more common causes is immune thrombocytopenia, a condition where the immune system mistakenly destroys its own platelets. When the platelet count falls below about 10,000 per microliter (normal is 150,000 to 400,000), petechiae and bruising from minimal contact become noticeable.
Low platelet counts can also result from viral infections, liver disease, heavy alcohol use, or bone marrow disorders. The petechiae from low platelets tend to show up on the lower legs first, since gravity increases pressure in those vessels, and they’re often accompanied by easy bruising elsewhere on the body or bleeding gums.
Infections
Several infections can cause petechiae, either by directly damaging blood vessels or by triggering a drop in platelets. Common viral infections, including some that cause the flu or a stomach bug, sometimes produce a few scattered spots that resolve as the illness clears.
The combination that demands immediate attention is petechiae with a fever. This pairing can indicate a serious bacterial infection, including meningococcal disease, a fast-moving infection that damages blood vessels throughout the body. In children especially, a non-blanching rash with fever requires urgent medical evaluation. The concern is that certain bacteria release toxins that destroy capillary walls, causing the rash to spread and the spots to grow larger over hours. Early antibiotic treatment is critical in these cases.
Vitamin C Deficiency
Vitamin C is essential for building the connective tissue that holds capillary walls together. Without enough of it, those walls weaken and begin to leak. The resulting petechiae often cluster around hair follicles, particularly on the shins and thighs. This is the early stage of scurvy, which is uncommon but does still occur in people with very restrictive diets, eating disorders, or conditions that impair nutrient absorption. Other signs include swollen or bleeding gums, fatigue, and slow wound healing.
Leukemia and Bone Marrow Disorders
Petechiae that are widespread across the body with no obvious mechanical cause can be a sign of leukemia or another bone marrow disorder. These conditions crowd out normal platelet production, meaning the body can’t keep up with everyday wear and tear on blood vessels. The spots tend to appear on the trunk and limbs rather than being confined to the face or chest, and they’re usually accompanied by other symptoms: persistent fatigue, unexplained weight loss, frequent infections, or unusual bleeding.
This is an uncommon cause of petechiae, but it’s the reason doctors take unexplained, widespread spots seriously. A simple blood test that counts platelets and other blood cells can quickly rule it in or out.
A Condition to Know in Children
Henoch-Schönlein purpura is a condition seen mostly in children that causes inflammation of small blood vessels. The hallmark is a raised, bruise-like rash on the legs, buttocks, and sometimes the arms or face. Unlike typical petechiae, these spots are often slightly raised and can look like patches of bruising. The rash usually appears alongside swollen, painful joints (particularly in the knees and ankles) and digestive symptoms like belly pain, nausea, or bloody stools. Most children recover fully, though the condition can affect the kidneys and may need monitoring.
How to Tell Harmless From Concerning
A few petechiae on your face after a coughing fit or a hard workout are nothing to worry about. The picture changes when petechiae are widespread or unexplained, when they appear alongside a fever, when you’re also bruising easily or bleeding from the gums, or when you feel unusually fatigued or unwell. In those situations, a blood test can check your platelet count, clotting function, and white blood cell levels, which together cover most of the serious possibilities. Petechiae combined with a high fever, especially in a child, warrants same-day evaluation rather than a wait-and-see approach.