[Overview of acquired palmoplantar keratodermas]. / Survol des kératodermies palmo-plantaires acquises.

Palmoplantar keratodermas affect a vast group of the population. Their origin is genetic or acquired. They represent manifestations of several distinct diseases. The precise semiologic examination is important for elucidating the differential diagnosis.

Environmental dew point and skin and lip weathering.

Xerosis represents a physiological response of the stratum corneum (SC) to environmental threats. The influence of the environmental dew point (DP) is not fully understood. This parameter is the air temperature at which the relative humidity is maximum. This study aimed to assess the relationship between the environmental DP and the water-holding capacity of the skin and lower lip vermilion. For comparison, SC property was evaluated after occlusive application of cooled and uncooled hydrogel pads. Electrometric measurements using a dermal phase meter (DPM) device were performed on the back of the hands, the cheeks and the lower lip of 40 healthy menopausal women. Assessments were performed in the outdoor conditions during winter and spring. The same measurements were recorded after hydrogel pads, at room temperature or cooled to 4 degrees C, were placed for 15 min on the test sites. The environmental DP was recorded at each evaluation time. The SC water-holding capacity was discretely influenced by the DP. In the open-air environmental conditions, a positive linear relationship was found on the cheeks between the DP and DPM values. The relationship was weaker on the lips. Conversely, a consistent increase in DPM values was recorded immediately after removal of the cooled and uncooled hydrogel pads. The observations made in the open-air testing conditions are consistent with the predicted events following the Arrhenius law. By contrast, the combination of cooling and occlusion by the hydrogel pads is responsible for the reverse effect on the SC.

High resolution skin colorimetry, strain mapping and mechanobiology.

SYNOPSIS: Skin colours are notoriously different between individuals. They are governed by ethnicities and phototypes, and further influenced by a variety of factors including photoexposures and sustained mechanical stress. Indeed, mechanobiology is a feature affecting the epidermal melanization. High-resolution epiluminescence colorimetry helps in deciphering the effects of forces generated by Langer's lines or relaxed skin tension lines on the melanocyte activity. The same procedure shows a prominent laddering pattern of melanization in striae distensae contrasting with the regular honeycomb pattern in the surrounding skin.

[How I explore... Hypochromic or achromic dermatoses]. / Comment j'explore... une dermatose hypochromique ou achromique.

Some skin disorders typically share in common a hypochromic or achromic aspect. The diagnostic approach relies on a directed evaluation of the medical history and a careful clinical examination. In addition, the cyanoacrylate skin surface biopsy helps establish the diagnosis.

[Kaleidoscopic overview of palmo-plantar papulosquamous skin disease]. / Dysidrose palmo-plantaire sous sous le kaléidoscope.

A pruritic vesicular, pustular or squamous eruption confined to the lateral aspect of fingers or toes corresponds to the overall pattern of dysidrosis. Such a clinical pattern is defined by its peculiar topography. It is encountered in diseases resulting from various etiologies. Thus, conceptually, dysidrosis is a common clinical aspect shared by diverse disorders related to different etiologies and pathomechanisms. The dermatopathological assessment and the patch test procedure shed some light on this nosological diversity. Allergic contact dermatitis, irritation dermatitis, mycids, alterations of acrosyringia, and drug or food reactions are eventually involved in this process. However, most cases of dysidrotic dermatoses do not disclose their origins and they remain idiopathic.

Manipulation of cadmium selenide nanorods with an atomic force microscope.

We have used an atomic force microscope (AFM) to manipulate and study ligand-capped cadmium selenide nanorods deposited on highly oriented pyrolitic graphite (HOPG). The AFM tip was used to manipulate (i.e., translate and rotate) the nanorods by applying a force perpendicular to the nanorod axis. The manipulation result was shown to depend on the point of impact of the AFM tip with the nanorod and whether the nanorod had been manipulated previously. Forces applied parallel to the nanorod axis, however, did not give rise to manipulation. These results are interpreted by considering the atomic-scale interactions of the HOPG substrate with the organic ligands surrounding the nanorods. The vertical deflection of the cantilever was recorded during manipulation and was combined with a model in order to estimate the value of the horizontal force between the tip and nanorod during manipulation. This horizontal force is estimated to be on the order of a few tens of nN.

[How I treat...hidradenitis suppurativa]. / Comment je traite...une hidradénite suppurée.

Hidradenitis suppurativa is a chronic and debilitating inflammatory disease. It presents as recurrent abcesses, sinus tracts and scarring. The condition usually develops in the axillae and groins, and more rarely involves the breasts, perineum and buttocks. There are many myths around hidradenitis suppurativa including its origin and pathomechanisms. Some antibiotics as well as corticosteroids and other immune downregulators are poorly effective in this stubborn condition. By contrast, TNF-alpha antagonists appear promising. Radical surgery is another effective option.

[How I explore ... eyebrow alopecia]. / Comment j'explore ... une raréfaction des sourcils.

The rarefaction or loss of eyebrow hair may represent an esthetic complaint or a peculiar finding associated with a given disease. The causal disorders correspond to a few dermatitides and several endocrine, auto-immune, infectious, neoplastic, traumatic, iatrogenic and genetic disorders.

[Merkel cell carcinoma: from diagnosis to therapeutic management]. / Le carcinome de Merkel: du diagnostic à la prise en charge thérapeutique.

Merkel cell carcinoma is a skin malignancy showing an increasing trend of incidence in the white population. Its viral origin due to the MC polyomavirus is likely. The diagnosis relies on the histological and targeted immunopathological examinations. Histoprognostic criteria remain to be defined. An assessment using medical imaging is important to establish. Treatments rely on surgery and radiotherapy. Chemotherapy is mandatory at the metastatic stage. Some biotherapies are potentially active.

[Cutaneous pseudolymphomas and pseudoclonality of lymphoid infiltrates]. / Pseudolymphomes cutanés et pseudoclonalité des infiltrats lymphoïdes.

Cutaneous pseudolymphomas represent an heterogeneous group of tumours resembling lymphomas by some clinical and histological aspects. They are distinguished, in particular, by their benign evolution. The histological and immunohistological examinations combined with molecular biology help to elucidate any diagnostic uncertainty. In these diseases, monoclonality and pseudoclonality must be distinguished in the lymphoid infiltrates. Searching for any specific etiology is important because removing the cause is likely to clear the lesions.

[How I explore...cutaneous lesions in cocaine and crack addicts]. / Comment j'explore...des lésions cutanées chez un toxicomane adepte de la cocaïne ou du crack.

Both cocaine and crack exert sympathetic and prothrombotic effects. The induced lesion may affect the skin, as well as other organ systems. Various types of vasculitis and infectious dermatoses are the predominant issues. In addition, tactile and visual hallucinations may occur suggesting insect crawling underneath the skin.

[How I explore....a pressure ulcer]. / Comment j'explore...une escarre de décubitus.

Pressure ulcers represent a major health problem causing both considerable morbidity and a high financial burden for the healthcare system. The geriatric segment of the population at risk of pressure ulcer is progressively increasing. This condition occurs at home, in old people's homes and in hospitals as well. The severity, duration and orientation of forces applied to the skin represent the most important factors responsible for pressure ulcers. Prevention measures are essential to reduce the prevalence of the disease.

[First-line dermatologic emergencies]. / Urgences dermatologiques de première ligne.

Dermatological emergencies encompass a series of distinct diseases of infectious, autoimmune and environmental origins. They account for a number of consultations at the general practitioner's office and in emergency units of medical centers. The concerned first line medical staffs are then facing some conditions with a dramatic potential. We review the most common conditions including urticaria, angioedema, infectious cellulitis, acute photodermatoses, the Lyell syndrome, some other paroxysmal severe adverse drug reactions, burns, erythroderma and the Kaposi-Juliusberg varicelliform eruption.

Involvement of reactive oxygen species in the bactericidal activity of activated carbon fibre supporting silver; Bactericidal activity of ACF(Ag) mediated by ROS.

An activated carbon fibre supporting silver (ACF(Ag)) was tested for its antibacterial capacity against Escherichia coli (E. coli). Water that has passed through ACF(Ag) demonstrated strong bactericidal ability. This activity decreased over the time suggesting that generated bactericidal species were short lifespan. Since formation of reactive oxygen species (ROS) might be catalysed by silver impregnated and/or ACF itself, implication of ROS and silver was evaluated by the use of ROS scavengers and a silver ions neutralizing agent. The role of ROS in the E. coli mortality was confirmed by the use of a molecular approach which revealed a strong expression of oxidative stress genes.