DERMIS: a computer system for assisting primary-care physicians with dermatological diagnosis.

DERMIS is a computerized skin disease diagnostic prompting system which has been derived from the prospective study of 5203 cases. It has been designed for use by non-dermatologists such as general practitioners. The program produces a list of reasonable diagnoses based on probabilities calculated using Bayes' theorem. Out of 221 precise diagnoses made by the dermatologist in the clinic, 42 groupings were created to encompass the most common or important diseases encountered in general practice. Four 'remainder' or 'send to specialist' groups were included for the 13% of uncommon conditions. The program, when tested by 'one out' analysis on the original cases, placed the correct diagnosis first on 76% of occasions, and within the first three on 95% of occasions. In 76 of 125 cases randomly selected from the data base, a request for diagnostic assistance had been made by the referring general practitioner. It has been estimated that in 54 of these 76 cases the DERMIS system could have provided differential advice with the correct diagnosis appearing at the top of the list. The system has been written in MUMPS and runs on an IBM-compatible desk-top computer. The software allows real time data entry. Arrangements are in hand for performing clinical trials of the system in general practice. If current performance is maintained, and the response to the system's output is favourable, then DERMIS might well enhance performance in medical decision making for the benefit of patients, medical services and budget holders.