Weathering of the hairless scalp: a study using skin capacitance imaging and ultraviolet light-enhanced visualization.

The balding scalp is particularly exposed to sunlight, hence, the overall ageing process modulated by ultraviolet and near-infrared light may be increased at this location. The induced changes are better revealed under ultraviolet light examination. Any alteration in the epidermal maturation is potentially reflected by stratum corneum changes observed as disturbances on skin-capacitance imaging.

Electrometric assessment of the effect of a zinc oxide paste in diaper dermatitis.

Diaper dermatitis affects nearly 50% of infants as well as some bed-ridden adults particularly in the elderly people. This condition is induced by irritation and maceration, and may be further exacerbated by Candida sp. colonization and infection. A key factor in the pathogenesis is the alteration in both the barrier function and the water-holding capacity of the stratum corneum. The purpose of this study was to assess the effects of an unmedicated zinc oxide-petrolatum paste and to observe for possible shielding and restoring effects on the water-holding capacity of the stratum corneum altered by diaper dermatitis. The paste appeared to load the hollow skin microrelief. It was inferred that this effect was responsible for a reticulated shielding effect. Compared with healthy skin and untreated diaper dermatitis, the application of the anhydrous paste resulted in a trend to normalize electrometric properties of skin reflecting the combination of transepidermal water loss and the water-holding capacity of the stratum corneum.

Chitin-glucan, a natural cell scaffold for skin moisturization and rejuvenation.

Two clinical studies were conducted to evaluate the tolerance and effects of a copolymer of chitin and beta-glucan, forming the exoskeleton of fungal cell walls, now supplied for cosmetic applications. A 6-week randomized, double-blind, placebo-controlled study was conducted on 13 volunteers with sensitive skin to compare with 0.5-2% formulations chitin-glucan applied twice daily. Biometrological evaluations showed that erythema did not develop, the water retention capacity of the stratum corneum increased and the transepidermal water loss moderately decreased. Another 16-week randomized, double-blind, placebo-controlled study was conducted on 20 men showing signs of ageing skin. A 1.5% chitin-glucan formulation was applied twice daily. Objective biometrological assessments showed a progressive increase in skin firmness and stratum corneum hydration when desquamation and skin roughness decreased. In conclusion, the chitin-glucan formulations appear safe. They significantly mitigate some signs of skin ageing and improve both stratum corneum hydration and skin barrier function.

[The agony of rubbish to clinicians]. / L'agonie du taratata auprès du clinicien.

The clinician is at the crossroad between scientific information and some rubbish presentations of low level communication. In this background, searching for objectivity is mandatory in clinical trials. We summarize the main aspects of assessment on nominal scale, ordinal scale, interval scale as well as on structured and non structured scales.

Kinetics of moisturizing and firming effects of cosmetic formulations.

The assessment of cosmetic efficacy is rarely performed in studies comparing different concentrations of active compounds. The aim of the present study was to determine the skin hydrating and the skin firming dose-response effects of cosmetic formulations enriched in compounds derived from algae and fish collagen. A series of factors were studied including the type of formulation (cream or serum), the concentration in active ingredients, the effect of repetitive applications, as well as any residual effect of the formulations after stopping their applications. The serum enriched in marine compounds showed a better moisturizing effect in short term. The cream appeared more active later, particularly following repeat applications. A sustained tensor (firming) effect was observed during treatment with both the lotion and the cream. However, no remnant firming effect was perceived after stopping treatment.

Biometrology of physical properties of skin in thyroid dysfunction.

OBJECTIVE: There is ample clinical evidence that skin is responsive to physiopathological levels of circulating thyroid hormones. The aim of the study was to assess some physical changes of the skin in the presence of moderate thyroid dysfunction. SETTING: University Hospital. PATIENTS AND METHODS: A total of 119 adults suffering from hypothyroidism or hyperthyroidism and 60 healthy controls were enrolled in this study. Hormonal dosages (TSH, fT3, fT4) were assessed in the serum. A series of biometrological assessments were also performed on the volar and dorsal aspects of the forearms. These included electrometric assessments (Nova Dermal Phase Meter, Corneometer), evaporimetry (Tewameter)), colorimetry (Mexameter), ultrasound shear wave propagation (Reviscometer) and squamometry X. Correlations were searched between each of the serum hormonal dosages and each of the biometrological parameters. RESULTS: The hormonal changes in the untreated patients with thyroid dysfunction were modest in intensity. A few outlier values with regard to the normal range were found for each biometrological parameter. No correlations were found between fT3 or fT4 and each of the physical parameters. By contrast, significant negative linear correlations were found between thyroid-stimulating hormone (TSH) and skin hydration measured by the Corneometer and the Nova DPM. CONCLUSION: This multipronged exploratory study shows that direct or indirect effects of TSH may influence the stratum corneum hydration. This correlation seemed very sensitive, as no other specific biophysical parameter was significantly correlated with the thyroid hormonal concentrations in the serum. However, our findings do not exclude the possibility of some other skin changes supervening in case of more severe thyroid dysfunction. The mechanism by which TSH alters the stratum corneum hydration is yet unknown.

[How I treat...the dry skin of the hands]. / Comment je traite...le "méhin" des mains sèches.

Suffering from dry skin on the hands is a common feature in the general population. This condition is influenced by daily habits and occupational duties. It commonly corresponds to the expression of irritation dermatitis modulated by climatic and other environmental conditions. Other diseases including allergic contact dermatitis, psoriasis and dermatomycosis can also be responsible for a similar clinical presentation. In the common discrete irritative type, a specifically designed cosmetic product may considerably improve the discomfort experienced by the patient. By contrast, the efficacy of most barrier creams remains unconfirmed. The chronic use of topical corticosteroids can lead to dependency and to progressive cutaneous atrophy.

Comparative effect of tacrolimus and betamethasone valerate on the passive sustainable hydration of the stratum corneum in atopic dermatitis.

BACKGROUND: There is ample evidence that the skin barrier function is altered in atopic dermatitis. Little information is available about the effect of topical corticosteroids and calcineurin inhibitors on this function. PURPOSE: To assess the water content and its rate of accumulation in the stratum corneum of atopic patients using an indirect electrometric method while on tacrolimus or betamethasone valerate treatment. METHOD: Twenty-one patients with moderate atopic dermatitis affecting both forearms completed this double-blind randomized study. One forearm was treated twice daily for 3 weeks with 0.1% tacrolimus ointment. The other forearm was similarly treated with 0.12% betamethasone valerate ointment. Electrometric measurements were made under continuous occlusion secured by a Nova Dermal Phase Meter sensor probe. Assessments were performed at inclusion, after the 3-week treatment and after a further 3-week follow-up out of treatment. RESULTS: During treatment, both compounds yielded a similar improvement in skin barrier function. Indeed, under probe occlusion, the rate of water accumulation was significantly decreased. This improvement was sustained after stopping the tacrolimus treatment. By contrast, the benefit was in part lost at the site that had been treated by betamethasone valerate. CONCLUSION: The difference in the effect of the 2 compounds may be due to the negative influence of betamethasone valerate on the epidermal metabolism leading to progressive atrophy of the tissue. The better preservation of the skin barrier function after stopping tacrolimus treatment may help retarding relapses of atopic dermatitis.

Skin capacitance mapping of psoriasis.

BACKGROUND: The pathobiological dynamics of psoriatic lesions are complex and difficult to perceive by clinical inspection alone. Non-invasive bioengineering methods may prove to be useful in this field. OBJECTIVE: To identify some subtle capacitance variations in the stratum corneum of chronic psoriasis lesions. METHOD: The newly developed method of skin capacitance imaging was used to provide non-optical images of the hydration of the superficial layers of the stratum corneum. RESULTS: Compared to the uninvolved skin, psoriatic lesions usually showed an overall lowered capacitance, admixed with foci of moderately higher capacitance. Still other sharply circumscribed blotches with higher capacitance were present. The latter aspect corresponded to inflammatory areas. Sweating appeared markedly impaired inside the lesions. The fingerprint of some patients was altered, thus potentially interfering with the current biometric security procedures using the same method. CONCLUSION: Skin capacitance imaging is a non-invasive, non-optical method that distinguishes three contrasting levels of stratum corneum hydration in psoriatic lesions. The lowest capacitance level probably corresponded to xerotic orthokeratosis. The medium capacitance level presumably identified foci of parakeratosis and clumps of neutrophils. The highest capacitance level suggested exsudation at the site of prominent vessel dilation and dermal inflammation. Impaired sweating in the psoriatic lesions may potentially interfere with body thermoregulation.

[How I prevent...exacerbation of atopic dermatitis]. / Comment je préviens...une exacerbation de la dermatite atopique.

Atopic dermatitis is under the influence of series of environmental factors. The contact with unsuited cleaning agents and rough textiles can exacerbate pruritus and inflammation. Preventive and adjuvant measures can thus help the care procedures of the disease. Appropriate hygiene measures and the use of emollients are particularly helpful. Clothing measures are also in place. Undergarments and pyjamas made of knitted natural silk are available. Other measures, sometimes corresponding to anecdotal claims--antihistamines, thermal cures, unconventional medicine, probiotics, chinese herbals, essential fatty acids--have not proven their preventive efficacy in atopic dermatitis.

[Quality of life, emollients and hydrating agents]. / Qualité de vie, emollients et agents hydratants.

So-called dry skin is a quite common and annoying condition. This skin may affect individuals that are otherwise healthy. It may be particularly severe and unpleasant in cases of ichthyosis, atopic dermatitis or psoriasis. The inductive effects of the environment must not be ignored. Emollients and hydrating agents for the stratum corneum can help relieve the clinical manifestations.

Dynamics of skin barrier repair following topical applications of miconazole nitrate.

The skin barrier function (SBF) is an important aspect of skin biology, particularly in the elicitation of inflammation. The SBF recovery rate after tape stripping and surfactant challenge can be assessed by measuring the transepidermal water loss (TEWL). Previous clinical studies have shown some inflammatory effect after topical applications of miconazole. The aim of this study was to compare the effect of pastes (petrolatum and 15% zinc oxide) containing or not miconazole nitrate on controlled impaired SBF. Fifteen volunteers were enrolled. In each subject, successive cyanoacrylate skin surface strippings were harvested from 5 sites of the volar forearm until TEWL raised above 15 g/cm(2)/h on all test sites. In addition, one daily soak session with a 0.2% dishwashing liquid further damaged the SBF. Each of the test formulations was applied twice daily for 5 days at two dosages, namely 1 and 2 mg/cm(2), on randomized test sites. Another site remained untreated. TEWL was measured daily for 5 days. A fastened SBF repair was observed on all treated sites, particularly where the largest amount of the products had been applied. A faster SBF recovery rate was obtained at the site receiving the miconazole nitrate paste. We conclude that the occlusive effect of a paste helped mitigate SBF defect. The adjunction of miconazole nitrate improved the efficacy.

Dandruff-associated smouldering alopecia: a chronobiological assessment over 5 years.

BACKGROUND: In some individuals, dandruff may be recurrent and even chronic. This represents a difficult-to-treat condition. Excessive hair shedding and diffuse alopecia may develop. OBJECTIVES: To evaluate the chronobiological aspects of dandruff, hair shedding and alopecia. METHODS: This study was performed in eight men suffering from such a scalp condition. They were examined 40 times at regular intervals for five consecutive years. Hair-density assessments and trichograms were performed at least twice per trimester on the parietal region of the scalp, corresponding to an area where dandruff was present. RESULTS: A positive correlation was found between the percentage of telogen hairs and dandruff severity as assessed by the squamometry index. Bimodal yearly biorhythms were found for dandruff severity, telogen counts and hair loss between two consecutive visits. The chronobiological fluctuations were prominent in some study participants, but remained inconspicuous in others. The biorhythms were almost synchronized in all participants, showing variations over the year. CONCLUSIONS: The biorhythms on the hair cycle in dandruff are not fundamentally different from those previously reported in subjects without dandruff. The periodicity may be an intrinsic feature of human skin.

Cellulite histopathology and related mechanobiology.

Cellulite, sometimes called gynoid lipodystrophy, is much more prevalent in women than in men. There are glaring discrepancies regarding the microanatomical descriptions of this condition in the literature. A lumpy aspect of the dermo-hypodermal interface is often cited, but it appears to represent a gender-linked characteristic of the thighs and buttocks without being a specific sign of cellulite. Incipient cellulite recognized by a discrete padded look or 'orange peel' aspect appears correlated with the presence of a network of focally enlarged fibrosclerotic strands partitioning the hypodermis and serving as a physiological buttress limiting the outpouching of fat lobules on pinching the skin. These connective tissue structures might represent a hormonal-dependent reactive process to sustained mechanical tensions caused by the adipocyte lobules. Full blown cellulite is recognized by a lumpy-bumpy and dimpled skin surface. It likely represents subjugation of the hypertrophic response of the hypodermal connective tissue strands when their resistance is overcome by progressive fat accumulation. In these cases, histological aspects reminiscent of striae distensae are identified within the hypodermal connective tissue strands. The mechanical properties of skin involved by cellulite process are altered, but may tend to resume to normal under treatment. These functional changes influence the mechanobiology of connective tissue cells, in particular the Factor XIIIa-positive dermal dendrocytes.

Revisiting dandruff.

Dandruff is a common scalp disorder affecting almost half of the postpubertal population of any ethnicity and both genders. It may, however, represent a stubborn esthetical disturbance often source of pruritus. Skin biocenosis, in particular the Malassezia spp. flora, plays a key aetiologic role, in combination with the unusual capacity of some corneocytes to be coated by these yeasts. Substantial evidence indicates that keratinocytes play an active role in the generation and expression of immunopathological reactions. This is probably the case in dandruff. Upon stimulation of a critical colonization of corneocytes by Malassezia yeasts, the release of pro-inflammatory mediators is increased. This could lead to the subclinical microinflammation present in dandruff. In seborrheic dermatitis, local deposits of immunoglobulins and the release of lymphokines are responsible for the recruitment and local activation of leukocytes leading to the eventual amplification of the inflammatory reaction. Some ancillary non-microbial causes of dandruff may operate through physical or chemical irritants. Many methods have been described for rating dandruff. Our favourite tools are clinical examination and squamometry. Dandruff can precipitate telogen effluvium and exacerbate androgenic alopecia. Antidandruff formulations exhibiting some direct or indirect anti-inflammatory activity can improve both dandruff and its subsequent hair cycle disturbance.

[How I treat...acne in adolescents: a strategic algorithm without antibiotic]. / Comment je traite...l'acné de l'adolescent: un algorithme stratégique sans antibiotique.

Acne is a multifaceted disorder. Its clinical presentation differs according to the age and gender of the subjects. Acne of the adolescent is a frequent disorder. Some topical and oral antibiotics have proven their efficacy. However, the risk of bacterial resistance may be a concern for the clinicians and their patients. Hence, a therapeutic strategy without antibiotics merits to be considered. Retinoids have a place of choice in this therapeutic strategy. Benzoyl peroxide and miconazole are also active and valuable agents in this therapeutic algorithm.

[How I treat. . . evanescent youth. Dating back using chemical peels]. / "Comment je traite. . . une jeunesse qui s'étiole. Remonter le temps par les peelings chimiques.

Chemical peels induce the destruction and exfoliation of the epidermis using selected caustic substances. The specific properties of these agents result in a limited and controlled destruction of epidermal layers and of the superficial dermis. The choice of the appropriate method, the preparatory phase and the post-peeling care are very important to reach optimal results. Some types of peeling are routinely used. We briefly report those designed for the superficial and medium depth peelings. The topical application of glycolic acid at high concentration induces a superficial peel resulting in shading of small wrinkles. Trichloracetic acid used at an appropriate concentration acts more deeply and thus represents a good indication for more severe signs of ageing. These peels have been used for decades by dermatologists to improve the visible signs of skin ageing and to treat some alterations of the cutaneous relief.

[From love apple to skin bouquet ... and if it also exhaled phaeromones?]. / De la pomme d'amour au bouquet de la peau humaine ... et si elle exhalait aussi des pheromones?

Skin exhales odours forming a bouquet which seems unique for each individual. The westernised socio-cultural behaviour tends to suppress them and to replace them by perfumes. The existence and the role of human phaeromones remain unsettled. Physiological and behavioural effects can be modulated by body odours and their putative phaeromones.