Pruritus in autoimmune connective tissue diseases

Pruritus is one of the most common and bothersome symptoms of skin disorders, and its clinical characteristics and related pathomechanisms have been well described in certain dermatologic conditions, such as atopic dermatitis and urticaria. Although pruritus is believed to be as common in cutaneous autoimmune connective tissue diseases (ACTDs) as in other inflammatory skin disorders, its true characteristics have not been elucidated either qualitatively or quantitatively. Pruritus is present in ACTDs with various prevalence rates, characteristics, and mechanisms depending on the disease types. Pruritus most frequently and severely affects the patients with dermatomyositis, in which itch is strongly correlated with disease activity and severity, thus increased itch could also indicate a disease flare. Patients with other ACTDs, including lupus erythematosus (LE), Sjögren syndrome (SS), morphea, and systemic sclerosis (SSc), also suffer from their fair share of pruritus. Unfortunately, the currently available treatments for ACTDs seem to have only limited and unsatisfactory effects to control pruritus. The extensive impact of pruritus on the patients' quality of life (QOL) and functioning warrants more targeted and individualized approaches against pruritus in ACTDs. This review will address the prevalence, suggested pathogenesis based on currently available evidences, and potential treatment options of pruritus in various ACTDs of the skin.