Left armpit 38 degrees right 36.5 degrees consider colds, infectious diseases, rheumatic immune diseases, endocrine diseases. 1. Colds that occur after exposure to wind and cold can cause colds and fever, and some will have nasal congestion, runny nose and sneezing. 2. Infectious diseases: for example, pneumonia, urinary tract infections, soft tissue infections can cause fever, which can be relieved by anti-infective drug treatment. 3. Rheumatic immune diseases: such as rheumatic fever, dry syndrome, connective tissue disease. 4. Endocrine system diseases: such as hyperthyroidism can also cause fever, thyroid function tests can be clearly diagnosed. So the left armpit 38 degrees right 36.5 to identify the cause of fever, for the cause of treatment.