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.

Annular infectious dermatoses.

Annular configuration is conspicuous in the clinical manifestation of many skin diseases and can be helpful for the diagnosis and differential diagnosis. Variations may include arciform, ring-form, annular, circinate, serpiginous, gyrated, polycyclic, targeted or figurate forms, in different colors, sizes, and numbers, with various textures and surfaces. In infectious dermatoses, the annular reactions can be specific or nonspecific, while the underlying mechanisms remain largely unknown. In the specific reactions caused by direct invasion of the pathogens, the contest between the centrifugal outspread of the infectious agents and the centripetal impedance of the host immune response is supposed to determine the final conformation. Examples include erythema infectiosum, orf, erythema multiforme, and pityriasis rosea of viral origin. Bacterial infections that may display annular lesions include erythrasma, erythema (chronicum) migrans of Lyme borreliosis, secondary syphilis, cutaneous tuberculosis, and leprosy. Superficial mycosis, such as dermatophytosis, candida intertrigo, tinea imbricata, and subcutaneous mycosis, such as chromoblastomycosis, and algae infection protothecosis, are characterized by annular progression of the skin lesions. The creeping serpiginous extension is an alarming sign for the diagnosis of cutaneous larva migrans. A better understanding of the virulence and pathogenicity of the pathogens and the way and type of immune response will help to clarify the pathogenesis.

Juvenile dermatomyositis in Thai children: Retrospective review of 30 cases from a tertiary care center.

BACKGROUND: Juvenile dermatomyositis is a rare condition, but it is the most common idiopathic inflammatory myopathy in pediatric patients. AIM: To study the clinical manifestations, investigations, treatment, clinical course, and outcomes of juvenile dermatomyositis in Thai children. METHOD: This retrospective study included juvenile dermatomyositis patients treated at Siriraj Hospital, a 2,300-bed national tertiary referral center in Bangkok, Thailand, from 1994 to 2019. RESULTS: Thirty patients (22 females and 8 males) were included with a female to male ratio of 2.7:1. Median age at diagnosis was 5.1 years (range, 2.6-14.8 years). Median duration of illness before diagnosis was 6.5 months (range, 0.3-84.0 months). Acute and subacute onset occurred in the majority of patients. Presenting symptoms included muscle weakness in 27/30 (90%), skin rash in 26/30 (86.7%), muscle pain in 17/26 (65.4%), and arthralgia in 4/18 (22.2%) of patients. Dermatologic examination revealed Gottron's rash, heliotrope rash, and periungual telangiectasia in 25/30 (83.3%), 21/30 (70.0%), and 15/24 (62.5%) of patients, respectively. Interestingly, scalp dermatitis was found in 8/21 (38.1%) of patients. The most commonly used treatment regimen in this series was a combination of prednisolone and methotrexate. During the median follow-up of 3.1 years (range, 0.0-18.5 years), only one-third of patients were seen to have monocyclic disease. Extraskeletal osteosarcoma at a previous lesion of calcinosis cutis was observed in one patient at 12 years after juvenile dermatomyositis onset. LIMITATIONS: This was a retrospective single-center study, and our results may not be generalizable to other healthcare settings. Prospective multicenter studies are needed to confirm the findings of this study. CONCLUSION: juvenile dermatomyositis usually poses a diagnostic and therapeutic challenge, which can be compounded by the ethnic variations in the clinical presentation, as observed in this study. Asian patients tend to present with acute or subacute onset of disease, and arthralgia and/or arthritis are less common than in Caucasian patients. Scalp dermatitis is not uncommon in pediatric juvenile dermatomyositis patients. An association between juvenile dermatomyositis and malignancy, though rare, can occur.

Challenging diagnosis of leprosy in a psychotic homeless patient with atypical clinical manifestations: an interesting case report.

BACKGROUND: A decision to diagnose certain skin diseases in patient undergoing psychotic break is challenging; this includes establishing the diagnosis of leprosy. Diagnosis of leprosy is established if there is at least one of the three cardinal signs of leprosy. Histopathological examination is not a gold standard, but remains useful in atypical or clinically suspicious cases. CASE PRESENTATION: We report for the first time, an interesting case of leprosy with atypical clinical manifestations in a psychotic homeless male with unknown history of present illness. Upon examination, hypopigmented macules, hyperpigmented macules, and plaques were observed, with unclear sensation impairment. Peripheral nerve thickening and acid-fast bacilli from slit-skin smear were not found. Histopathological examination from hypopigmented macule on the upper right limb showed no granulomatous reaction and other histopathological features of leprosy. Although the condition did not fulfill the cardinal signs of leprosy, we found lagophthalmos, claw hands, pseudomutilation of fingers and toes. Therefore, the diagnosis of suspected leprosy was established. The patient was hospitalized and attempts to administer oral rifampicin and clofazimine were made. Several days after treatment, annular erythematous macules appeared on the patient's face, abdomen, and back. Histopathological examination results on sample taken from erythematous macule and right sural nerve were consistent with the diagnosis of leprosy with reversal reaction. CONCLUSION: In certain conditions, histopathological examination of the skin and nerves are a highly rewarding test in establishing a diagnosis of leprosy.

Dermatology practice in the times of the COVID-19 pandemic.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is implicated in the ongoing pandemic across the globe since December 2019. It was first notified by China from Wuhan on 31 December 2020 and transmission to healthcare workers was first reported on 20 January 2020. Human-to-human transmission is mainly by droplet infection. At present no effective vaccine is available. Our speciality needs to collectively address the urgent issue of risk of transmission in dermatology practice. A case series of Coronavirus Disease 2019 (COVID-19) from Wuhan described that 41.3% of their patients may have acquired the infection from the hospital. Of all the infected health care workers, 77.5% worked in general wards and departments. These data highlight the significant risk of nosocomial transmission of COVID-19 and also the higher risk in general wards and departments compared to the emergency room or intensive care unit. Dermatology patients are generally seen in clinics and in outpatient departments in hospitals. Patients wait together in the waiting area, intermingle and then are seen by the physician in their chamber. This can cause transmission of the pathogen among patients and from patient to physician. Social distancing, hand hygiene and the use of personal protective equipment are important for preventing the spread of infection and dermatology practices also have to incorporate these aspects. Telemedicine is becoming an important tool for the management of dermatology patients in these times. At-risk patients in dermatology also need to be given priority care. Protocols for the use of immunosuppressants and biologics in dermatology during the pandemic are being developed.

Basal cell carcinoma associated with non-neoplastic cutaneous conditions: a comprehensive review.

Basal cell carcinoma (BCC) can be a component of a collision tumor in which the skin cancer is present at the same cutaneous site as either a benign tumor or a malignant neoplasm. However, BCC can also concurrently occur at the same skin location as a non-neoplastic cutaneous condition. These include autoimmune diseases (vitiligo), cutaneous disorders (Darier disease), dermal conditions (granuloma faciale), dermal depositions (amyloid, calcinosis cutis, cutaneous focal mucinosis, osteoma cutis, and tattoo), dermatitis, miscellaneous conditions (rhinophyma, sarcoidal reaction, and varicose veins), scars, surgical sites, systemic diseases (sarcoidosis), systemic infections (leischmaniasis, leprosy and lupus vulgaris), and ulcers. The relationship between the BCC and the coexisting non-neoplastic condition may be coincidental or possibly related to the development of the BCC; alternatively, the development of the BCC may be unrelated to the coexisting non-neoplastic conditions and secondary to either a Koebner isomorphic response or a Wolf isotopic response in an immunocompromised district of skin. This paper reviews several of the case reports and studies that describe the association of BCC with these non-neoplastic cutaneous conditions.

Erythroderma: a prospective study of 309 patients followed for 12 years in a tertiary center.

Erythroderma is characterized by erythema and scaling affecting more than 80% of the body surface area. It is potentially life-threatening, and diagnosis of the underlying disease is a challenge. Despite laboratory improvements, many cases remain idiopathic. We aimed to analyze clinical and laboratory findings of 309 erythrodermic patients to find clues to the etiologic diagnosis. We performed a prospective study at the University of São Paulo Medical School, from 2007 to 2018, with patients with acquired erythroderma. Clinical, laboratory, histology, and molecular biology data were collected. The median age at diagnosis was 57 years, with a male-to-female ratio of 2.2. Eczema was the most frequent etiology (20.7%), followed by psoriasis (16.8%), Sézary syndrome (12.3%), drug eruption (12.3%), atopic dermatitis (8.7%), and mycosis fungoides (5.5%). Other diagnoses (6.8%) included pemphigus foliaceous, paraneoplastic erythroderma, adult T-cell leukemia/lymphoma, dermatomyositis, pityriasis rubra pilaris, lichen planus, bullous pemphigoid, and leprosy. In 52 patients (16.8%), it was not possible to elucidate erythroderma etiology. Atopic dermatitis developed erythroderma at an earlier age (median 25 years; P = 0.0001). Acute onset was associated with drug reactions and atopic dermatitis (median time from erythroderma to diagnosis of 1 and 1.5 months, respectively; P = 0.0001). Higher immunoglobulin E levels were observed in atopic dermatitis (median 24,600 U/L; P = 0.0001). Histopathology was helpful and was consistent with the final diagnosis in 72.4%. Monoclonal T-cell proliferation in the skin was observed in mycosis fungoides (33.3%) and Sézary syndrome (90.9%). At the last assessment, 211 patients (69.3%) were alive with disease, 65 (21.7%) were alive without disease, and 27 (9.1%) died with active disease. Erythroderma is a challenging syndrome with a difficult diagnostic approach. Younger age and higher immunoglobulin E levels are associated with atopic dermatitis; acute onset is observed in drug eruptions and atopic dermatitis. Histopathology and molecular biology tests are essential tools in the investigation of erythroderma.

A new presentation of isolated cutaneous Rosai-Dorfman disease: Eruptive xanthoma-like lesions.

Rosai-Dorfman disease or sinus histiocytosis with massive lymphadenopathy is a benign lympho-histiocytic proliferative disorder initially described with bilateral painless lymphadenopathy (90 %), fever, leukocytosis, elevated ESR, anemia, and polyclonal hypergammaglobulinemia (90 %). Extranodal forms occur in 43% of cases, the skin being the most common site. Around 10% of patients have skin lesions and in 3%, the disease is limited exclusively to the skin. Here, we report a male patient who presented with pure cutaneous lesions which mimic eruptive xanthoma clinically. However, the diagnosis was established histo pathologically. So, high level of clinical suspension is critical to avoid missing such cases.

Lepra Lepromatosa con incio neural puro. A propósito de un caso / No disponible

En la lepra lepromatosa, cuando los troncos nerviosos periféricos son invadidos producen lesiones en la medida en que la enfermedad progresa de manera simétrica y dejan graves secuelas en etapas avanzadas de la enfermedad. Se trata de un paciente masculino, de 56 años de edad, con antecedentes de haber sido tratado por la especialidad de neurología por más de 20 años, debido a que tenía trastornos de la sensibilidad en miembros inferiores, en forma de calcetín que había sido diagnosticado como neuropatía sin causa aparente que acude a consulta de cuerpo de guardia del Hospital Manuel Ascunce de Camagüey, refiriendo que desde hacía unos años presentaba lesiones en forma de manchas por todo el cuerpo, que no le picaban. Al examen dermatológico se constata cuadro cutáneo diseminado constituido por placas infiltradas eritematosas, de bordes mal definidos, en número de más de una veintena, acompañadas de trastornos de la sensibilidad y disminución del vello a ese nivel. Además, con infiltraciones difusas de cara y pabellones auriculares, trastorno de la sensibilidad en miembros inferiores y troncos nerviosos engrosados. La variedad neurítica pura es muy discutida y se cree que los casos que fueron diagnosticados como tales presentaron lesiones cutáneas que pasaron inadvertidas y no dejaron secuelas

In lepromatous leprosy, when the peripheral nervous trunks are invaded they produce lesions to the extent that the disease progresses symmetrically and leave serious sequelae in advanced stages of the disease. This is a 56-year-old male patient with a history of having been treated by the specialty of neurology for more than 20 years, because he had sensory disorders in the lower limbs, in the form of a sock that had been diagnosed as a neuropathy without apparent cause, he went to the on call unit at the Manuel Ascunce Hospital in Camagüey, saying that for some years he had had lesions in the form of spots all over his body that did not itch. The dermatological examination revealed a disseminated cutaneous plaque composed of infiltrated erythematous plaques with poorly defined edges, in a number of more than twenty, accompanied by disorders of sensitivity and hair loss at that level. Also with diffuse infiltration of the face and ears, sensory disturbance in the lower limbs and thickened nerve trunks. The pure neuritic variety is very controversial and it is believed that the cases that were diagnosed as such presented cutaneous lesions that went unnoticed and did not leave sequels