A footwear system having a plurality of temperature sensors determines the emergence of an ulcer or pre-ulcer on a person's foot. After the plurality of temperature sensors generate a plurality of discrete temperature data values, the system and method form a temperature map representing substantially the actual geometric shape of at least a portion of the foot, and the distribution of temperatures of the at least a portion of the foot. Next, the method and system determine whether the temperature map presents at least one of a plurality of prescribed patterns, and produces output information indicating an emergence of an ulcer or a pre-ulcer on a given portion on the foot. The output information is produced as a function of whether the temperature map is determined to present the at least one of the plurality of prescribed patterns.