Finding tiny purple dots spreading across your lower legs or ankles can be unsettling, especially when they appear suddenly. Although some skin changes are caused by minor irritation or pressure, small, flat spots that do not fade when pressed can sometimes signal bleeding beneath the skin.One possible explanation is petechiae, a term for tiny spots caused by blood leaking from small blood vessels into the surrounding skin. Petechiae are not a disease themselves. They are a sign that something has caused small amounts of bleeding under the skin, and the underlying reason can range from relatively minor strain to a medical condition requiring urgent evaluation.Knowing what these spots look like, what might cause them, and which accompanying symptoms are warning signs can help you make a safer decision about what to do next.1. What Do Petechiae Look Like?Petechiae are very small, flat spots that typically appear red, purple, or reddish-brown. They are often around 1–2 millimeters across and may occur individually or in clusters.Unlike hives or many insect bites, petechiae generally do not form raised bumps. They can resemble tiny pinpricks beneath the surface of the skin.Common characteristics include:Small, pinpoint marks: Individual spots are usually very small, although clusters may look like a larger discolored patch.Red, purple, or brown coloring: The exact appearance can vary depending on the skin tone and how long the spots have been present.Flat skin: The affected area usually feels smooth rather than swollen.Little or no fading under pressure: Petechiae generally do not blanch, meaning their color does not disappear when pressure is applied.Petechiae may be easier to notice on the ankles, feet, and lower legs, but they can develop anywhere on the body.Importantly, not every small purple spot is petechiae. Other skin conditions can look similar, and appearance alone cannot establish the cause.2. How to Check Whether the Spots Fade Under PressureOne feature that can help distinguish petechiae from certain inflammatory rashes is whether the spots blanch when pressed.You may hear this described as a blanching test or a glass test. Although it can provide a useful observation, it cannot determine whether the condition is dangerous.How to check safelyLook at the spots in good lighting.If the skin is not painful or injured, gently press a clean, clear drinking glass against the affected area.Observe whether the spots visibly fade under the pressure.
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