Reddish dots on the body usually refer to red papules, which may be caused by contact dermatitis, eczema, allergic purpura and other diseases. 1. Contact dermatitis: acute or chronic inflammatory reaction that occurs in the contact area of the skin mucosa after the skin comes into contact with exogenous substances such as ointment, which may appear as erythema, papules and small blisters. 2. Eczema: often manifested in the skin erythema on the basis of the appearance of pinhead to corn size red papules, papules. 3. Anaphylactic purpura: Before the onset of the disease, there are often upper respiratory tract infection, low-grade fever, general malaise and other prodromal symptoms, followed by the emergence of red pimples, usually within 24 hours to develop into a pinpoint to soybean-sized purpura. The reason for the red papules on the body is more, it is recommended that patients go to the hospital in time to clarify the cause of the disease, under the guidance of the doctor for standardized treatment.