A red patch on the body may be caused by purpura, urticaria, dengue, psoriasis and other diseases.
1. Purpura: allergic purpura, idiopathic thrombocytopenic purpura, can cause subcutaneous capillary rupture, causing ecchymosis, may lead to a patch of red patches on the body.
2. Urticaria: temporary increase in vascular permeability of the skin mucosa, caused by limited edema, can also cause itchy skin ecchymosis, resulting in a patch of red patches on the body.
3. dengue: it is infected by type b hemolytic streptococcus, causing bacterial infectious disease of deep skin tissues, resulting in edematous erythema of the skin, with clear boundaries, and the surface is tense and shiny, which also causes a patch of red plaques on the body.
4. Psoriasis: a chronic, relapsing, inflammatory, systemic disease caused by a combination of heredity and the environment, which may lead to scaly erythema of the skin, or plaques, and may also lead to a patchy red plaque on the body.
There may be other reasons for having a patch of red patches on the body, and you need to go to the hospital in time to get checked out and clarify the cause.