Spider nevi

Introduction Spider mites are a special type of telangiectasia. It occurs on the face, neck and chest, and there are other parts. A small small hemangioma with a diameter of 2 mm or less at the center, with many capillaries extending around and branching, looks like a red spider on the skin. If the center of the needle is pressed with a pencil tip, the spider mites will disappear, because the blood flow direction of the spider mites flows from the center point to the peripheral capillary branch. If the central part is compressed, the blood flow is blocked, and the spider mites disappear due to ischemia.

Cause

Spider mites are common in acute, chronic hepatitis or cirrhosis, and are also seen in pregnant women and healthy people. The incidence of spider mites in patients with acute hepatitis is about 1%, while that of chronic hepatitis is about 54%. The appearance of spider mites is often parallel to the state of liver function. When liver function deteriorates, spider mites can increase dramatically. After the liver function improved, the cockroach could change from bright red to brownish black, and then disappeared.

an examination

Related inspection

Blood routine liver function examination

The center of the spider's cockroach is pressed with a cotton swab or a matchstick, and the radial small vascular network is dissipated, and will appear after the pressure is removed.

1. The disease can occur on its own, more common in pregnant women, cirrhosis patients and thyrotoxicosis.

2. Also visible in normal children.

3. Skin lesions are more common in the face, especially for the underarms, the upper part of the cheeks and the front chest and hands.

4. The lesion is a centrally protruding red point-like papule, surrounded by red small blood vessels that are radially distributed like spiders.

5. The transparent slide is lightly pressed and sometimes pulsating.

6. The skin lesions disappeared when the rash center applied pressure.

7. Skin lesions are often single or multiple, especially when there is liver damage.

Differential diagnosis

Differential diagnosis:

Hereditary hemorrhagic telangiectasia

At the time of physical examination, it is found that a special telangiectasia ranging from red to purple appears on the face, lips, nose and mouth mucosa, and at the tips of the fingers and toes. Similar lesions may be present on the gastrointestinal mucosa, causing gastrointestinal bleeding. Some patients may also have a history of repeated massive nosebleeds. Some patients may have pulmonary arteriovenous fistula. Arteriovenous fistula causes shunting from right to left (short circuit), causing difficulty breathing, fatigue, cyanosis or polycythemia. Due to clinical manifestations caused by infected or non-infected emboli, a brain abscess, transient ischemia or stroke may first occur. Brain or spinal arteriovenous fistula can occur in some families, manifested as subarachnoid hemorrhage, epilepsy or hemiplegia. If there is a family history of pulmonary arteriovenous fistula, pulmonary CT or brain MRI in adolescence will be helpful in diagnosis. Most patients' tests are usually normal except for iron deficiency anemia.

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