Red rashes on the face and body may be related to atopic dermatitis, folliculitis, generalized eczema and other causes. 1. Allergic dermatitis: when allergens enter the body through skin or mucous membrane contact, ingestion, injection and other channels, they can cause the body to undergo an abnormal immune response, which may be manifested as red rashes on the face and body. 2. Folliculitis: Hair follicles on the face and body are infected by bacteria, which can cause a localized inflammatory reaction and the appearance of red pimples. 3. Generalized eczema: an inflammatory skin reaction with intense itching caused by a variety of internal and external factors, which can lead to an inflammatory reaction of the skin, which can be manifested as a red rash on the face and body, characterized by symmetrical distribution of rashes, itchiness, and recurrent episodes. There are many other causes of red rash on face and body (such as insect bite dermatitis, etc.), it is recommended to go to the hospital in time to clarify the cause of the disease and standardize the treatment under the guidance of the doctor.