Evaluation of a new method of assessing pruritus and antipruritic drugs.

A new method (Pain-Track) for recording subjective symptoms was evaluated for its capacity to quantify clinical itch. The Pain-Track system includes portable data loggers carried by the patients, a personal computer with a software package for storage and analysis of the data and a terminal unit to connect the loggers and computer. Every 60 min a signal from the logger commands the patient to mark his presence and rate the itch intensity. During night time the hourly buzz can be turned off but the intensity rate can be adjusted whenever wanted. The antipruritic effect of betamethasone dipropionate and its cream base was studied according to a double-blind, crossover protocol in 30 adult outpatients with atopic dermatitis, 26 of whom completed the study. Analysis with parametric and nonparametric methods showed that the itch intensity was significantly lower during active treatment than with placebo. Onset of the antipruritic action was rapid. Examination of the 'itch profile' revealed that atopics have more intense itch both in the mornings and evenings than during the day. It is concluded that by using a drug with known antipruritic effect we have shown that Pain-Track is a useful tool for assessing clinical pruritus and the antipruritic effects of drugs. The main advantages are possibilities for frequent recordings, surveillance of compliance improving authenticity, and storage and analysis of a large amount of data.