Xerotic skin and impairment of barrier function associated with itch

Dry xerotic skin, which is characterized by a rough, scaly, and flaky skin surface, has been associated for decades with the somatosensory sensation of itch. The list of clinical conditions of dry skin and itch as shown in Table 30.1 includes common skin diseases such as atopic dermatitis and senile pruritus, as well as systemic diseases such as uremia and human immunodeficiency virus (HIV). It is important to note that not every xerotic skin is associated with itch; for example, patients with ichthyosis vulgaris usually do not complain of itch. Although the clinical associations between itch and dry skin is well established, data of studies examining the skin hydration and transepidermal water loss, which are objective measures for skin hydration and barrier impairment, provide conflicting results on such an association. This chapter will provide a review of the existing data and possible mechanisms of itch associated with xerotic skin.