Retrospective Study of Intraepidermal Nerve Fiber Distribution in Biopsies of Patients With Nummular Eczema

Transcriptomic, Epigenomic, and Neuroanatomic Signatures Differ in Chronic Prurigo, Atopic Dermatitis, and Brachioradial Pruritus

Scratching and scratch-induced injuries, including neuroanatomical alterations, are key characteristics of chronic pruritus entities of different origins. The aim of this study was to link gene expression (array hybridization, qPCR) with DNA methylation (array hybridization) and neuroanatomy (PGP9.5 staining) in chronic nodular prurigo (CNPG), atopic dermatitis (AD), brachioradial pruritus (BRP), and matched healthy controls. Specific signatures of gene expression and DNA methylation clearly discriminated pruritic lesional skin from nonpruritic skin in CNPG and from healthy skin of volunteers, respectively. Although intraepidermal nerve fiber density was indiscriminately reduced, the level of epidermal branching, assessed by a semiquantitative pattern analysis, differentiated the entities (CNPG > BRP > AD). Correspondingly, repellent SEMA3A showed the highest expression in AD, whereas axonal growth-promoting nerve GF was most prominent in CNPG and BRP. Overexpression of genes for nerve fiber regeneration (NELL2/NFKB/ARTN) was found in AD and CNPG but not in BRP. Our findings suggest that differential branching patterns rather than mere innervation density separate chronic itch conditions and reflect disease-specific local expression profiles. In pruritic dermatoses (AD and CNPG), nerve injury and subsequent sprouting may primarily result from chronic scratching, whereas genuine neuropathy is expected to underlie BRP.

Discoid (nummular) eczema in the paediatric setting - An Australian/New Zealand narrative

Discoid (nummular) eczema is a common and distinctive eczema variant, which has not been studied in depth. Although the principles of management are similar to that of classic atopic dermatitis, distinctions are made due to its unique presentation and persistent clinical course in children. Australian and New Zealand dermatologists with an interest in paediatric eczema developed a consensus narrative to assist clinicians in diagnosing and treating this subtype of eczema. Identifying triggers, potent topical corticosteroids under occlusion, skin barrier support and management of pruritus are first-line therapies, however, many eventually require systemic immunomodulatory agents.

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.

Neuropathic Itch: Routes to Clinical Diagnosis

Neuropathic itch occurs due to damage of neurons of the peripheral or central nervous system. Several entities, including metabolic, neurodegenerative, orthopedic, infectious, autoimmune, malignant, and iatrogenic conditions, may affect the somatosensory system and induce neuropathic itch. Due to the complex nature of neuropathic itch, particularly concerning its clinical presentation and possible etiological factors, diagnostic work-up of this condition is challenging. A detailed medical history, especially in regard to the itch, and a comprehensive physical examination are relevant to detect characteristic signs and symptoms of neuropathic itch and to rule out other possible causes for chronic itch. Complementary diagnostic exams, especially laboratory tests, determination of the intraepidermal nerve fiber density via a skin biopsy and radiological examinations may be indicated to confirm the diagnosis of neuropathic itch and to identify underlying etiological factors. Functional assessments such as quantitative sensory testing, nerve conduction studies, evoked potentials, or microneurography may be considered in particular cases. This review article provides a comprehensive overview of the diagnostic work-up recommended for patients with neuropathic itch.

Nummular Eczema: An Updated Review

Background:

Nummular eczema may mimic diseases that present with annular configuration and the differential diagnosis is broad.

Objective:

This article aimed to provide an update on the evaluation, diagnosis, and treatment of nummular eczema.

Methods:

A PubMed search was performed in using the key terms “nummular eczema”, “discoid eczema”, OR “nummular dermatitis”. The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews. The search was restricted to English literature. The information retrieved from the above search was used in the compilation of the present article. Patents were searched using the key terms “nummular eczema”, “discoid eczema”, OR “nummular dermatitis” in www.google.com/patents and www.freepatentsonline.com.

Results:

Nummular eczema is characterized by sharply defined, oval or coin-shaped, erythematous, eczematous plaques. Typically, the size of the lesion varies from 1 to 10cm in diameter. The lesions are usually multiple and symmetrically distributed. Sites of predilection include the lower limbs followed by the upper limbs. The lesions are usually intensely pruritic. The diagnosis is mainly clinical based on the characteristic round to oval erythematous plaques in a patient with diffusely dry skin. Nummular eczema should be distinguished from other annular lesions. Dermoscopy can reveal additional features that can be valuable for correct diagnosis. Biopsy or laboratory tests are generally not necessary. However, a potassium hydroxide wet-mount examination of skin scrapings should be performed if tinea corporis is suspected. Because contact allergy is common with nummular eczema, patch testing should be considered in patients with chronic, recalcitrant nummular eczema. Avoidance of precipitating factors, optimal skin care, and high or ultra-high potency topical corticosteroids are the mainstay of therapy. Recent patents related to the management of nummular eczema are also discussed.

Conclusion:

With proper treatment, nummular eczema can be cleared over a few weeks, although the course can be chronic and characterized by relapses and remissions. Moisturizing of the skin and avoidance of identifiable exacerbating factors, such as hot water baths and harsh soaps may reduce the frequency of recurrence. Diseases that present with annular lesions may mimic nummular eczema and the differential diagnosis is broad. As such, physicians must be familiar with this condition so that an accurate diagnosis can be made, and appropriate treatment initiated.

Complex regional pain syndrome: a focus on the autonomic nervous system

PURPOSE

Although autonomic features are part of the diagnostic criteria for complex regional pain syndrome (CRPS), the role of the autonomic nervous system in CRPS pathophysiology has been downplayed in recent years. The purpose of this review is to redress this imbalance.

METHODS

We focus in this review on the contribution of the autonomic nervous system to CRPS pathophysiology. In particular, we discuss regional sympathetic and systemic autonomic disturbances in CRPS and the mechanisms which may underlie them, and consider links between these mechanisms, immune disturbances and pain.

RESULTS

The focused literature research revealed that immune reactions, alterations in receptor populations (e.g., upregulation of adrenoceptors and reduced cutaneous nerve fiber density) and central changes in autonomic drive seem to contribute to regional and systemic disturbances in sympathetic activity and to sympathetically maintained pain in CRPS.

CONCLUSIONS

We conclude that alterations in the sympathetic nervous system contribute to CRPS pathology. Understanding these alterations may be an important step towards providing appropriate treatments for CRPS.

Causes, pathophysiology, and treatment of pruritus in the mature patient

Chronic itch is a common and debilitating health condition in the elderly. There are several common causes of itch in the mature population, such as skin xerosis, immunosenescence, and neuropathic changes. In addition, skin diseases, such as seborrheic dermatitis and stasis dermatitis, systemic conditions (end-stage renal disease and diabetes), or psychogenic derailments, such as depression, anxiety, and dementia, can all serve as triggers of pruritus. Polypharmacy, a common occurrence among the elderly population, may also serve as a cause of itch that may or may not be accompanied by dermatitis. Such medications as μ opioids and calcium channel blockers have been found to have a connection with pruritus in the advanced aging population. Determining the exact trigger for pruritus in the elderly may be especially challenging, because itch can be idiopathic in many cases. The role of treatments should not only take into account elimination of various underlying cutaneous, systemic, or psychogenic conditions associated with itch but also focus on the skin changes that are characteristic of the aging process. Development of such treatment options can be guided by elucidation of the mechanisms underlying the pathophysiology of itch in the geriatric population.

Chronic pruritus in the elderly: pathophysiology, diagnosis and management

Chronic itch in the elderly is a common problem, with a significant impact on quality of life and sleep in elderly patients. Chronic itch may be attributable to several causes, including dry skin, immunosenescence and neural degeneration. Itch may also be caused by skin diseases, such as seborrhoeic dermatitis and stasis dermatitis; systemic conditions, such as end-stage renal disease and diabetes; and psychogenic conditions, such as depression and anxiety. The use of polypharmacy may also cause itch, with or without a rash. Specifically, thiazides and calcium channel blockers have been known to cause itch in elderly patients. Management should be tailored according to the underlying dermatological or systemic aetiology of itch. Topical treatment is the mainstay of therapy, providing special emphasis on skin hydration and barrier repair. In addition, topical and oral medications that target the nervous system and reduce neuronal hypersensitization, such as gabapentin and selective antidepressants, have a role in treating patients with severe chronic itch. Furthermore, management must account for changes in metabolism and pharmacokinetics of drugs in the aging population in order to prevent the occurrence of adverse effects.

The pleasurability of scratching an itch: a psychophysical and topographical assessment

BACKGROUND

Scratching an itch is perceived as being pleasurable. However, an analysis of topographical variations in itch intensity, the effectiveness of scratching to provide itch relief and the associated pleasurability has not been performed at different body sites.

OBJECTIVES

To examine the role of scratching pleasurability in providing itch relief by investigating whether itch intensity is perceived differently at three different sites and to assess a potential correlation between the pleasurability and itch attenuation induced by scratching.

METHODS

Itch was induced on the forearm, ankle and back using cowhage spicules in 18 healthy subjects. These sites were subsequently scratched by an investigator with a cytology brush immediately following itch induction. The intensity of itch with and without scratching at these sites and the pleasurability of scratching were recorded by taking visual analogue scale ratings at 30-s intervals.

RESULTS

Mean itch intensity and scratching pleasurability ratings at the ankle and back were significantly higher than on the forearm. For the forearm and ankle, the greater the itch while scratching, the higher was the pleasurability. A higher baseline itch was linked to a higher itch reduction secondary to scratching in all tested areas. Pleasurability paralleled the curve of itch reduction for the back and forearm; however, scratching pleasurability at the ankle remained elevated and only slightly decreased while itch was diminishing.

CONCLUSIONS

There are topographical differences in itch intensity, the effectiveness of scratching in relieving itch and the associated pleasurability. Experimental itch induced by cowhage was more intensely perceived at the ankle, while scratching attenuated itch most effectively on the back.

Pruritus

Health-related quality of life (QoL) is a patient-reported outcome that describes the impact of the disease in question to all aspects of persons' life, including psychosocial, emotional, physical, and functional impact. As such, health-related QoL is particularly relevant in conditions that have no physical signs and need to rely on patient reports to know whether they are improving or not. Work is beginning in pruritus to develop instruments that can measure pruritus-related QoL. This article reviews the instruments that have been developed and used in pruritus and also reviews the literature regarding the impact of pruritus on QoL.