Scratch urticaria, also known as skin scratching disorder. It may be caused by low immunity, as well as allergies, bacterial or fungal infections and other factors.
1. Low immunity: When the immunity is lowered, the body is subjected to external stimuli, which can easily cause mast cells and other inflammatory cells to degranulate, releasing inflammatory factors, thus forming skin scarring.
2. Allergy: When the body comes into contact with allergens, or is in a sensitized state, it leads to capillary dilatation under the skin, extravasation of plasma components, and limited edema of the skin. When scratching the skin with hands, or scraping the skin with a blunt instrument, it will cause skin scratches.
3. Bacterial or fungal infections: When the body is infected by bacteria or fungi, the body will produce antigenic antibody reactions, which can cause cutaneous scars.
There may be other causes of skin scarring, so you can go to the hospital for a complete examination to clarify the situation and take appropriate measures.