A universal applicator for applying therapeutic heat to a localized skin area of a patient. The applicator includes a casing dome whose open base is maintained in spaced relation to the skin area to define an air flow zone therebetween. Coaxially mounted at an intermediate position within the dome is a motor-driven fan which creates a negative pressure region in the dome above the fan and a positive pressure region therebelow, whereby air drawn from the negative pressure region is propelled into the positive pressure region from which it is discharged into the air flow zone. From this zone, the air is returned to the negative pressure region, thereby creating a circulatory flow loop minimizing the discharge of air into the atmosphere outside the flow zone. Mounted coaxially within the dome in the negative pressure region is an electric heater ring formed by a helical resistance coil. When the heater ring is energized, the air circulating in the loop passes through the coil and is raised in temperature to a level that is a function of fan velocity, the higher the velocity the lower the temperature level.