Objective assessment of acne.

A precise and reliable assessment of acne severity is unarguably the most essential clinical method when it comes to monitoring and choosing optimal treatment in the daily practice. Since the early 1960s, different severity assessment systems have been described in the literature. The two commonly used concepts are global gradings and lesion counting. Both systems have been controversially discussed as to which is more reliable and providing an objective outcome measurement tool; however, both have some subjectivity involved. More objective methods for assessing the severity of acne vulgaris include photography, fluorescence photography, polarized light photography, video microscopy, and multispectral imaging. Such techniques have limitations such as high cost, complex and sophisticated apparatus, and a sometimes time-consuming imaging process. There are newly developed technologies that could avoid the problems of inter- and intrarater subjectivity.