Heat on the bottom of the foot may be due to the following reasons: 1. It may be peripheral neuritis of the foot. This condition is common when the foot is often cold, or the skin of the foot is exposed to some chemicals, which leads to it. Usually, in addition to fever, there may be other abnormal sensations of nerves, such as a sensation of ants crawling, or some numbness pain. 2, it may be a plant nerve disorder. Usually in addition to plantar fever, but also accompanied by some symptoms of the whole body, such as chest tightness, palpitations, panic, insomnia, dreamy, more nervous, this situation is particularly seen in women around 50 years old menopause. 3, it may be skin allergies. Usually the soles of the feet are in contact with some easily allergic substances, such as mites or some other chemical substances, resulting in local skin allergies, resulting in local hot, swollen feeling, usually accompanied by itching. If severe, it can cause systemic symptoms and a generalized rash of some kind.