A method of monitoring a patient's foot forms a thermogram of the sole of at least one foot of the patient, and determines whether the thermogram presents at least one of a plurality of prescribed patterns. The method also compares the thermogram against a prior thermogram of the same foot, and produces output information indicating the emergence of an ulcer on a given portion on the at least one foot as a function of 1) whether the thermogram is determined to present the at least one pattern, and 2) the comparison with the prior thermogram, which shows non-ulcerated tissue at the given location.