Petechiae are tiny, flat dots on the skin that measure just 1 to 2 millimeters across, roughly the size of a pinpoint. They appear red, purple, or brown depending on your skin tone and how long they’ve been present. Unlike many other rashes, petechiae are completely flat. You can’t feel them by running your finger over the skin.
Size, Color, and Texture
Each individual spot is about the size of the tip of a ballpoint pen. They often appear in clusters, which can make them look like a scattered spray of tiny dots rather than a single mark. On lighter skin, fresh petechiae tend to look bright red or reddish-purple. On darker skin tones, they may appear darker purple or brown and can be harder to spot. Over time, all petechiae shift from red toward brown as the trapped blood breaks down beneath the skin’s surface.
The key visual feature is that petechiae are not raised, bumpy, or textured in any way. If you close your eyes and touch the area, you won’t feel anything different from the surrounding skin. This flatness is what separates them from bug bites, hives, or many allergic rashes that create a bump or welt.
How to Tell Petechiae Apart From Other Rashes
The simplest way to check is the glass test. Press the side of a clear drinking glass firmly against the dots and watch what happens. Most rashes will fade or temporarily disappear under pressure because you’re pushing the blood out of the small vessels beneath the skin. Petechiae don’t fade. The dots stay visible through the glass because the blood has already leaked out of the vessels and is sitting in the surrounding tissue. There’s no blood flow left to push away.
This non-blanching quality is the single most reliable visual clue. If the spots vanish when you press on them and reappear when you release, they’re not petechiae.
Petechiae vs. Purpura vs. Bruises
All three involve blood leaking under the skin, but size is what separates them. Petechiae are the smallest at 1 to 2 millimeters. Purpura refers to the same type of bleeding when the spots grow larger than a few millimeters, often up to about a centimeter. Anything bigger than that is typically classified as ecchymosis, which is the medical term for a bruise. You can think of these as a spectrum: pinpoint dots, larger blotches, and full bruises, all caused by the same basic process of blood escaping into the tissue.
Where They Typically Show Up
Petechiae can appear almost anywhere on the body, but certain locations are more common depending on the cause. When they result from physical strain like forceful coughing, vomiting, or heavy weightlifting, they tend to cluster around the face, eyelids, and neck. That’s because straining increases pressure in the tiny blood vessels of the head and upper chest, causing them to burst in those areas.
When petechiae are caused by something systemic, like a low platelet count or an infection, they’re more likely to appear on the legs, feet, and trunk. They can also show up inside the mouth, on the inner eyelids, or on other mucous membranes. Spotting them in the mouth or on the inner lining of the eyelid is worth noting because it suggests the cause is more than just surface-level strain.
Common Causes
Many cases of petechiae are completely harmless and caused by brief physical strain. A hard coughing fit, a bout of vomiting, crying intensely, or even straining during childbirth can produce a scattering of dots around the face and eyes that fades within a few days without any treatment.
Certain medications can also trigger petechiae as a side effect. Anti-seizure drugs, some antibiotics like penicillin, and blood-thinning medications are among the more common culprits. In these cases, the dots usually appear more widely across the body rather than concentrated in one area.
Less commonly, petechiae point to something more serious. Low platelet counts from conditions like immune thrombocytopenia, leukemia, or viral infections can cause widespread petechiae because the blood lacks enough platelets to seal tiny vessel breaks. Severe bacterial infections, including meningococcal disease, can also produce a rapidly spreading petechial rash. This is one reason why the glass test is taught so widely to parents: a non-blanching rash spreading quickly alongside a high fever is a medical emergency.
What to Watch For
A few petechiae appearing on your face after vomiting or coughing hard are rarely cause for concern and typically resolve on their own within a week or two. The pattern that warrants prompt attention is petechiae that appear without an obvious physical trigger, spread quickly, or show up alongside other symptoms like fever, fatigue, unusual bruising, or bleeding gums. Multiple signs together suggest the cause may be in the blood itself rather than a one-time burst of pressure.
Pay attention to the trajectory. Petechiae from strain stay put and gradually fade from red to brown to nothing. Petechiae from a systemic cause tend to keep appearing in new areas, often getting more numerous over hours or days rather than fading.