Aetiology, pathogenesis and management of neuropathic itch: A narrative review with recent updates.

Neuropathic itch is a relatively common yet under-reported cause of systemic pruritus. It is a debilitating condition often associated with pain, which impairs the patient's quality of life. Although much literature exists about renal and hepatic pruritus, there is a dearth of information and awareness about neuropathic itch. The pathogenesis of neuropathic itch is complex and can result from an insult at any point along the itch pathway, ranging from the peripheral receptors and nerves until the brain. There are several causes of neuropathic itch, many of which do not produce any skin lesions and are thus, often missed. A detailed history and clinical examination are necessary for the diagnosis, while laboratory and radiologic investigations may be needed in select cases. Several therapeutic strategies currently exist involving both non-pharmacological and pharmacological measures, the latter including topical, systemic, and invasive options. Further research is ongoing to clarify its pathogenesis and to design newer targeted therapies with minimal adverse effects. This narrative review highlights the current understanding of this condition, focusing on its causes, pathogenesis, diagnosis, and management, along with newer investigational drugs.

Pseudoxanthomatous or xanthelasmoid mastocytosis: Reporting a rare entity.

Mastocytosis is a disease characterized by abnormal and pathologic increase in mast cells in the cutaneous tissue and extracutaneous organs such as the bone marrow, liver, spleen, lymph node and gastrointestinal tract. Cutaneous mastocytosis comprises of four major clinical variants: solitary and multiple mastocytomas, urticaria pigmentosa, diffuse cutaneous mastocytosis and telangiectasia macularis eruptiva perstans. Cutaneous mastocytosis of the xanthelasmoid type is a rare variant of diffuse mastocytosis. It is clinically characterized by the typical yellowish hue and is accompanied histologically by mast cells infiltrating far into the lower dermis. Here we report one such rare case.

A retrospective study of the utility of targeted phototherapy in vitiligo.

BACKGROUND: Targeted phototherapy is a recent advance in the treatment of vitiligo, involving selective treatment of vitiligo patches with no effect on surrounding areas. Although it has been in use for a few years, little data is available regarding its safety and efficacy. AIMS: A retrospective study to determine efficacy and safety of targeted phototherapy in vitiligo. METHODS: One hundred and thirty four patients (male: 53, female: 81) who received targeted phototherapy and completed 11 or more sittings were included. Treatment was given once a week using the Lumera phototherapy system, a broadband ultraviolet B source, starting at 150 mJ/spot and after excluding a sunburn reaction, with increments of 50 mJ every week up to a maximum of 1000 mJ/patch. Chi-square test for linear trends was used for statistical analysis. RESULTS: The most common sites involved were the legs and a majority (70.9%) had non-segmental vitiligo. Response was mild in 78 (58.2%) patients, moderate in 50 (37.3%) and excellent in 6 (4.5%) patients. Response was directly proportional to the number of sittings with more patients showing moderate and excellent responses with an increase in the number of sittings. The most common site for an excellent response was the trunk while the lower limbs were involved in most cases with a moderate or mild response. Side effects were seen in 27 (20.2%) patients, the commonest being erythema. LIMITATIONS: This is a retrospective uncontrolled study. Further, the effects of adjuvant treatment were not assessed. CONCLUSIONS: Targeted phototherapy is a useful treatment for vitiligo with mild adverse effects, though response is mild or moderate and appears to be directly proportional to the number of treatments received.

Disfiguring facial lesions and loss of sensation.

Hansen disease (leprosy) continues to be prevalent in some regions of Africa, Asia, and South America, and each year 100 to 300 cases are reported in the United States, especially in immigrants and patients exposed to armadillos. Treatment depends on patient presentation. Hansen disease remains highly stigmatized, though it is now clear that it is not readily transmitted through casual physical contact.

Cutaneous problems in elderly diabetics: A population-based comparative cross-sectional survey.

BACKGROUND: There are few population-based studies on prevalence of cutaneous problems in diabetes mellitus. AIMS: To identify skin problems associated with diabetes mellitus among elderly persons in a village in Kerala. METHODS: In this population-based cross-sectional survey, we compared the prevalence of skin problems among 287 elderly diabetics (aged 65 years or more) with 275 randomly selected elderly persons without diabetes mellitus. RESULTS: Numbness, tingling and burning sensation of extremities,"prayer sign", finger pebbling, skin tags, stiff joints and acanthosis nigricans were noted more frequently in diabetics as compared to non-diabetics. Ache in extremities, dermatophytosis, candidiasis, seborrheic keratoses/dermatosis papulosa nigra, xerosis/ichthyosis, idiopathic guttate hypomelanosis, nonspecific itching, and eczema were equally frequent in both groups. Among the diagnostic categories, neurovascular, metabolic and autoimmune findings were associated with diabetes mellitus, whereas bacterial and fungal infections were not. LIMITATIONS: Initial misclassification errors, no laboratory confirmation of dermatological diagnosis during survey, coexistence of findings related to aging and not analyzing the effects of glycemic level, concurrent diseases and medications. CONCLUSIONS: Numbness, tingling and burning sensation of extremities, prayer sign, finger pebbling, skin tags, stiff joints and acanthosis nigricans were associated with diabetes mellitus among elderly persons in a village in Kerala.

Understanding itch: an update on mediators and mechanisms of pruritus.

Pruritus is the most common symptom secondary to skin diseases. Advances in the fields of neurobiology, immunology and physiology have made it possible for us to understand and unravel the deeper pathophysiological basis of pruritus. This review aims to update our current understanding of the mechanisms and mediators of pruritus. Special attention is paid to endogenous itch mediators particularly newly identified ones like endovanilloids, opioids, neurotrophins, cannabinoids, proteases and cytokines. Various theories explaining the peripheral encoding of itch are reviewed. Multiple neural pathways including the central itch pathways as well as supraspinal processing of itch and brain areas involved in pruritus are highlighted. Apart from peripheral itch mediators, spinal neural receptors are also involved in control of itch and should form part of the development of a novel antipruritic strategy. Further studies are required to fill the lacunae in our current understanding of the pathophysiology of pruritus.