The most common cause of inexplicable swelling and pain on the left side of the foot is infection, especially if the patient has a history of tinea pedis or damage to the soft tissues of the skin, which can easily lead to secondary lymphangitis, also known as dermatitis, in which the patient will have local swelling and pain, also accompanied by significant fever and increased laboratory blood count, and should be treated promptly with anti-infective therapy. In the acute stage, the limb should be elevated to promote venous blood return, which can relieve the patient’s discomfort, and with effective treatment, the symptoms usually improve gradually. Some patients are affected by dorsalis pedis fasciitis, which is associated with strain, especially excessive weight bearing and exertion. With age, osteophytes and degenerative changes can also occur, and the patient will also show pain, which can lead to increased local swelling after activity, mainly by choosing physiotherapy methods, which can be done with local heat or massage, which can also relieve the condition.