1 to 2 mm haemorrhages in skin are known as:
**Core Concept**
Petechiae are small, pinpoint hemorrhages that occur in the skin or mucous membranes due to the rupture of small blood vessels, leading to bleeding.
**Why the Correct Answer is Right**
Petechiae are typically 1 to 2 mm in size and are usually caused by the rupture of capillaries or small venules, leading to localized bleeding. This can be due to various factors such as trauma, infection, or hematological disorders. The bleeding is confined to the dermal layer of the skin, resulting in the characteristic petechial spots.
**Why Each Wrong Option is Incorrect**
**Option A:** Purpura is a larger hemorrhage, typically greater than 3 mm in size, and is usually caused by bleeding into the dermal and subcutaneous tissues.
**Option B:** Ecchymosis refers to a larger area of bruising, often resulting from trauma or bleeding into the soft tissues.
**Option C:** Hematoma is a localized collection of blood outside of blood vessels, often resulting from trauma or bleeding into the soft tissues.
**Clinical Pearl / High-Yield Fact**
It's essential to note that petechiae can be a sign of underlying conditions such as platelet disorders, vasculitis, or infections like meningococcemia.
**Correct Answer:** . Petechiae.