Pruritus is an unpleasant sensation that entails to scratching. According to recent recommendations of International Forum for the Study of Itch chronic pruritus is defined as lasting at least 6 weeks. In 2007 IFSI proposed a new classification of pruritus, which will be revised and developed in the future. The classification of pruritus is based primarily on clinical symptoms and divides pruritus into two main categories: the pruritus with the presence of primary or secondary skin lesions or the pruritus without any skin lesions. In-order pruritus is classified to six categories according to the patomechanism of itch.

The pathophysiology of itch is multifactorial and not entirely discovered. The transmission of stimuli by nerves and the role of specific spinal neurons carrying receptors for gastrin-releasing peptide are of special interest.

There are many mediators of pruritus: histamine, acethylcholine, neuropeptides, proteases and opioids. Endovanilloids are the new prospective mediators group under investigation. The research on itch plays a key role in the development of future strategies for management of various types of pruritus.