Gil Yosipovitch

Perceived stress has long been known to alter the dynamic equilibrium established between the nervous, endocrine and immune system and is widely recognised to trigger or enhance pruritus. However, the exact mechanism of how the major stress response systems, such as the hypothalamus‐pituitary adrenal (HPA) axis and the autonomic nervous system induce or aggravate chronic itch, has not been elucidated. The limbic regions of the brain such as the prefrontal cortex and hippocampus are deeply involved in the regulation of the stress response and intersect with circuits that are responsible for memory and reward. According to the ‘Polyvagal Theory’, certain limbic structures that serve as a ‘higher brain equivalent of the parasympathetic nervous system’ play a foremost role in maintaining body homoeostasis by functioning as an active vagal brake. In addition, the limbic system has been postulated to regulate two distinct, yet related aspects of itch: (i) the sensory‐discriminative aspect; and (ii) the affective‐cognitive aspect. Chronic stress‐induced itch is hypothesised to be caused by stress‐related changes in limbic structure with subsequent rewiring of both the peripheral and central pruriceptive circuits. Herein, we review data suggesting that a dysfunctional parasympathetic nervous system associated with chronic stress may play a critical role in the regulatory control of key candidate molecules, receptors and brain structures involved in chronic itch.

There have been considerable advances in our understanding of the pathophysiology of pruritus in recent years. The purpose of this review was to highlight itch entities in women, and in particular pruritic vulvar dermatoses that women experience among different age groups. Unique temporal shifts may contribute to the etiology of many of these conditions. These changes lead to cyclical changes in the skin's basic composition. Specifically, estrogen receptors have been detected on keratinocytes that respond to rising and falling levels of estrogen. These receptors lead to changes in skin hydration, collagen content, and in the concentration of glycosaminoglycans that form the skin barrier. In addition, hormonal pH changes associated with the menstrual cycle may be an important factor in the aggravation of itch as increasing pH is known to activate the proteinase-activated receptor-2, a well-known itch mediator. Common pruritic conditions in women that will be discussed include atopic and irritant dermatitis, psoriasis, lichen sclerosus, infectious vulvovaginitis, vulvovaginal candidiasis, atrophic vulvovaginitis, squamous cell carcinoma, lichen simplex chronicus, and neuropathic itch. We also examine pruritic conditions associated with pregnancy including pemphigoid gestationis, polymorphic eruption of pregnancy, intrahepatic cholestasis of pregnancy and atopic eruption of pregnancy. Finally, acceptable and contraindicated antipruritic agents in pregnancy are examined.

Pain is a common feature of cancer with an estimated prevalence rate between 52% and 77%.¹ Itch is the most common dermatologic symptom and is also a common feature of lymphoma.² However, no studies have been performed examining the prevalence rates of pain and itch in common skin cancers. Squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) are the 2 most common types of nonmelanoma skin cancer (NMSC). They have a rapidly increasing incidence in the United States, with nearly 4 million new cases of NMSC diagnosed each year.³ The purpose of the present study was to assess the prevalence and intensity of pain and itch among the 2 most common skin cancers.

Background  To date, no study has compared the clinical characteristics, malignancy associations, and treatment of dermatomyositis in predominantly Caucasian vs. Asian populations.Materials and methods  This prospective study was conducted to compare clinical characteristics of dermatomyositis, its relationship to malignancy, and treatment between two tertiary medical centers in the USA and Singapore. A total of 19 newly‐diagnosed patients in the USA and 15 patients in Singapore were enrolled. Dermatomyositis or amyopathic dermatomyositis were diagnosed based on clinical assessment, skin and muscle biopsies, and muscle testing.Results  Ninety‐five percent of patients in the USA group were of Caucasian descent, while 93% of patients in the Singapore group were of Chinese descent. Both groups were predominantly female. Pruritus was the most common initial symptom reported in both groups, while periungual erythema and Gottron’s papules were the most common skin presentations. Heliotrope eruption was more common in the Singapore group, occurring in 80% of patients vs. 32% of patients in the USA group (P = 0.007). Three patients in the Singapore group developed a malignancy, with two of these patients having nasopharyngeal carcinoma. None of the USA patients developed malignancies in a follow‐ up period of 2–5 years. Immunosuppressive steroid sparing therapy with hydroxychloroquine was more frequently used in Singapore, while topical tacrolimus was more frequently used in the USA.Conclusion  The clinical presentations of dermatomyositis vary among different ethnic populations. Chinese patients with dermatomyositis have a significant risk for nasopharyngeal carcinoma.

Olympic athletes are vulnerable to traumatic, environmental and infectious skin manifestations. Although dermatological complaints are frequent among Olympians, there is a scarcity of literature that reviews sports-related dermatoses among Olympic athletes. A comprehensive review of PREMEDLINE and MEDLINE searches of all available literature through to January 2011 was conducted, focusing on sports-related dermatological presentations as well as the key words ‘Olympic athletes’ and ‘skin diseases’. Common skin conditions can be harmful and even prohibitive for competition. Common aetiologies of dermatological conditions related to sports include: skin infections with dermatophytes such as tinea pedis and tinea corporis, bacteria such as pitted keratolysis, and folliculitis and viruses such as herpes gladiatorum. Frictional dermatoses occur commonly and include athlete’s nodules, jogger’s itch, frictional blisters, callosities and talon noir. Trauma can cause haematomas such as auricular haematomas. Due to long training hours in the sun, many endurance athletes experience high levels of UV radiation and a higher risk for both melanoma and non-melanoma skin cancer. Pre-existing dermatoses can also be aggravated with practice and competition; in particular, atopic eczema and physical urticarias. Infrequent dermatoses are susceptible to misdiagnosis, delay in treatment and needless biopsies. This review highlights the diagnosis and management of sports-related dermatoses by the following general categories of Olympic sport: endurance, resistance, team sport, and performing arts.

Trigeminal trophic syndrome (TTS) is the historic name for neuropathic self-induced facial ulceration from abnormal sensory symptoms leading to uncontrolled scratching. Anatomic co-localization of sensory loss (numbness) plus neuropathic itch and pain permits painless scratching. If the itch is severe, some patients will scratch to the point of causing self-injury. Patients may be unaware or may conceal the fact that their lesions are self-induced and thus the diagnosis presents a clinical challenge. Many cases remain undiagnosed, leading to unnecessary and ineffective tests, procedures, and prescribing. We document a patient with a central cause of TTS — multiple cerebral vascular accidents — and summarize the presentation, pathogenesis, and treatment options.

Scalp pruritus is a common complaint that is considered a diagnostically and therapeutically challenging situation. Scalp skin has a unique neural structure that contains densely innervated hair follicles and dermal vasculature. In spite of the recent advances in our understanding of itch pathophysiology, scalp itching has not been studied as yet. In this review, we summarize the current knowledge on the neurobiology of scalp and hair follicles as well as itch mediators and provide a putative mechanism for scalp itch with special emphasis on neuroanatomy and pathophysiology.