A pimple on the ball of the foot may be an insect bite dermatitis, or it may be a pigmented nevus, plantar wart, corns, etc., which needs to be seen promptly for a clear diagnosis. Insect bite dermatitis is most common in summer, and it occurs in infants and young children or people with heavy body odor. Mosquito venom stimulate the skin easily cause local skin allergic reaction, if the bite of the foot can appear pimples, and with itching. Pigmented nevus is a kind of benign skin growth, the cause of which is not completely clear at present, and is related to heredity, trauma, friction and other factors. Nevus pigmentosus can grow on any part of the body, which is why it can appear as a lump on the ball of the foot. Nevus pigmentosus in the center of the foot usually does not become malignant, but nevus pigmentosus that grows on friction-prone areas such as the front of the foot, the heel and the bottom of the toes has a certain risk of malignant transformation. Plantar warts are a disease caused by infection with the human papilloma virus, which causes abnormal proliferation of keratinocytes. The disease is usually caused by localized broken parts coming into contact with contaminated shoes and socks, etc. Rough and hard papules or plaques are formed, so bumps can appear on the soles of the feet. Chicken eye is caused by excessive proliferation of the cuticle of the skin, and local skin long-term friction, extrusion related, often wear leather shoes or high-heeled shoes, often exercise or engage in heavy physical labor people are prone to have. Long-term friction of the skin, the stratum corneum for the protection of subcutaneous tissue overgrowth, the formation of thick callus-like keratinocytes, accompanied by pain, etc., can appear in the soles of the feet with pimples. It is recommended that patients with pimples on the soles of their feet go to a regular hospital in time for a clear diagnosis and standardized treatment under the guidance of a doctor.