Skin petechiae

Introduction Extensive or localized skin, submucosal hemorrhage, forming red or dark red spots on the skin and mucous membranes, about 3-5 mm in diameter or larger. Usually the diameter is less than 2 mm. Subcutaneous or submucosal plaque hemorrhage caused by increased vascular permeability due to various factors such as injury, poisoning, infection, allergies or thrombocytopenia. The point is a red or purple blood spot on the body, also known as bleeding point in medicine.

Cause

1. Extravascular factors: If the perivascular tissue is weak due to degeneration, atrophy and relaxation, it is prone to bleeding and form purpura. Extravascular factors are more common in senile or cachexia purpura. Capillaries and small blood vessels are slightly affected by a slight external force, which can cause rupture and hemorrhage.

2. Vascular factors: refers to the purpura formed by the leakage of blood from the blood vessels to the outside of the blood vessels due to damage of the capillary wall. Purpura caused by vascular factors accounted for the first place in all purpura. After a small blood vessel injury in a normal person, the blood vessel immediately undergoes a reflex contraction, and the local blood flow is slowed down to promote hemostasis. If the peripheral blood vessels are brittle, the permeability is increased, and the vasomotor function is abnormal, it is easy to cause hemorrhagic purpura due to extravasation of blood from the blood vessels. The hemorrhage caused by vascular factors is characterized by capillary fragility test, but the bleeding time and clotting time are normal. The most common form of such purpura is allergic purpura. Second, bacterial or viral infections, vitamin C deficiency, chemical factors, etc. can cause damage to the blood vessel wall and cause purpura. In addition, there is an unclear increase in the brittleness of the blood vessel wall, which is common in women. The purpura can disappear on its own and has no adverse consequences. It is called simple purpura.

3. Platelet factors: Platelets play an important role in the process of hemostasis. Thrombocytopenia or defects in platelet function may result in decreased or lost hemostasis, and are prone to purpura. Thrombocytopenia can be seen in idiopathic thrombocytopenia, secondary thrombocytopenia (also known as symptomatic purpura, thrombocytopenia due to bone marrow hematopoietic disorders, seen in aplastic anemia, leukemia, cancerous bone metastasis), radiation Substances and chemicals destroy megakaryocytes, which reduce platelet production and severe infections (such as typhoid fever, meningitis, sepsis) and excessive platelet destruction.

4. Coagulation factor: Coagulation factor deficiency often causes coagulopathy and causes purpura. These diseases are rare, the causes are mostly congenital, and a few are acquired (mainly caused by liver disease). Patients with purpura should be examined for blood routine, platelet count, bleeding time, clotting time, capillary fragility test, skin and mucous membrane microcirculation, hemorheology and coagulation factors.

an examination

Related inspection

Coagulation factor activity assay platelet test item blood test

1 vascular purpura: very common, due to damage to the blood vessel wall or its fragility and permeability, common in immune (such as allergic purpura), infectious (such as sepsis), abnormal vascular structure (such as heredity) Hemorrhagic telangiectasia and other diseases such as abnormal proteinemia, simple or senile purpura. Check that there is no abnormality other than the beam arm test may be positive.

2 platelet abnormal purpura: the most common, mostly due to thrombocytopenia, increased and dysfunction, if the buccal mucosa of the buccal mucosa or blood blisters, often suggesting severe bleeding, should be actively treated.

3 coagulation mechanism disorders, including clotting factor deficiency, circulating anticoagulant substances or fibrinolysis hyperemia, generally caused by blood clotting mechanism disorders caused by joint blood, muscle hematoma and visceral hemorrhage, less skin purpura It only shows large ecchymoses, and it has obvious abnormalities in the examination of coagulation, which can be differentiated from purpura caused by vascular purpura and platelet abnormalities. The treatment of purpura varies according to the cause.

Differential diagnosis

Extensive or localized skin and submucosal hemorrhage, forming red or dark red spots on the skin and mucous membranes, about 3-5 mm in diameter or larger. Those larger than 5 mm are called ecchymoses, and local bulges or fluctuations are hematoma.

Common diseases that cause defects

1, epidemic hemorrhagic fever: visible in the oral mucosa, chest and back, under the armpits of varying sizes of bleeding points or ecchymosis, or a strip-like, scratch-like bleeding points.

2, thrombocytopenic purpura: sputum and ecchymosis can occur in any part of the skin and mucous membranes, but more distal extremities.

3, cerebrospinal meningitis: skin, mucous membranes may have sputum, ecchymosis.

4, sepsis: visible a variety of skin damage, with sputum, ecchymosis, scarlet fever-like rash, measles-like rash common.

5, trauma: skin will appear dark purple ecchymosis after a bruise, more serious bruises, hematoma may occur.

6, allergic purpura: more manifested as skin purpura. The sables vary in size and can be fused into pieces to form ecchymoses. Purpura is mainly limited to the limbs, especially the lower limbs and buttocks.

7, acute leukemia: more than a few patients with bleeding, varying degrees of severity, the site can be throughout the body, manifested as sputum, ecchymosis, nosebleeds, bleeding gums and menorrhagia, fundus bleeding.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.