If you feel hot all over, there are usually several factors: 1. The most common factor is infectious, when the body is infected with bacteria, viruses, fungi or other pathogenic microorganisms, such as mycoplasma and chlamydia, the body will have a pyrogenic reaction, which means that you will feel hot. 2. The clinical symptom of feeling hot all over the body can occur in rheumatic diseases or rheumatoid arthritis or tuberculosis, dermatomyositis, systemic lupus erythematosus, or dry syndrome. 3. In endocrine and metabolic diseases, such as hyperthyroidism and hyperadrenocorticism, the body will feel hot all over the body due to the hyper metabolism of the endocrine gland and the accelerated breakdown of heat.