Large flat bumps on the body may be caused by hives, insect bites, herpes and other causes. 1. Urticaria: It is an allergic reaction. Skin contact with food, drugs and other allergens cause capillary dilation, increased permeability, resulting in limited edema of the skin to form a wind, appearing on the body with large flat bumps. 2. Mosquito bites: If the number of big flat bumps on the body is not large, it may be caused by mosquito bites, after being bitten by mosquitoes, the skin will appear big flat bumps, accompanied by itching. 3. Herpes: Herpes is caused by a viral infection of the skin, and may also appear as large flat bumps with blisters, accompanied by intense itching, and may also have a fever. The situation of large flat bumps on the body suggests that the patient timely consultation, by the doctor clear diagnosis, follow the doctor’s instructions for targeted treatment, so as to avoid delays in the adverse effects of the disease.