A system and method for portably delivering a therapeutic dose of heat to the skin to relieve pain, reduce accommodation of thermal nerve receptors, promote healing, and deliver transcutaneous medications. The heating device is user programmable or pre-programmed to deliver according to a variety of cycles, patterns and algorithms. The cycles, patterns, and algorithms of the heat are programmable parameters, are under the user's control, and increase the effectiveness and efficiency of the device. The heating algorithms are designed to interact with an individual users thermal nerve receptors and other tissue characteristics and to reduce the tendency of the receptors to accommodate to the external stimuli with back pain, muscular pain, dysmenorrhea, headaches, fibromyalgia, post-herpetic neuralgia, nerve injuries and neuropathies, and sprains and strain. The device can also be used in conjunction with existing medical devices such as Transcutaneous Electrical Nerve Stimulators (TENS) to increase the effectiveness of TENS devices.