G. Rabbiosi

Effects of water temperature on surfactant-induced skin irritation.

Surfactant‐induced irritant reactions may be elicited by several endogenous and exogenous factors. Among these, surfactant concentration, and duration and frequency of exposure play important rotes. The study focuses on the influence of water temperature in determining damage of the skin barrier. 10 subjects of both sexes entered the study. 4 areas (4×4 cm2) were randomly selected on the volar forearm and were treated with a daily open application of 5% sodium lauryl sulphate for 4 days. The solutions were at 3 temperatures: 4®, 20® and 40 ®C. One site served as untreated control. On the 5th day, skin irritation was evaluated using transepidermal water loss (TEWL) measurements, erythema (a* value), skin reflectance (L* value), hydration (capacitance) and desquamation (stripping). The results show a significant effect of the solutions temperature in determining skin irritation (P < 0.001), Skin damage was higher in sites treated with warmer temperatures and a highly significant correlation (P < 0.001) between irritation and temperature was found. In conclusion, the study shows that water temperature during washing has an important effect on the onset of irritant contact dermatitis.

Ranking of surfactant skin irritancy in vivo in man using the plastic occlusion stress test (POST)

Irritant effects and disturbance of water‐holding capacity induced by surfactants were investigated using the plastic occlusion stress test (POST) technique. 4 surfactants (sodium lauryl sulphate (SLS), sorbitan monolaurate, cocoamidopropyl betaine and benzalkonium chloride) and an amphoteric/ nonionic (A/ N) mix were investigated. 1 × daily for 3 days, test surfactants were applied to marked sues (open) on the volar forearm. After 24 h occlusion with a plastic chamber on the 4th days. skin surface water loss (SSWL) (g/m2h) was recorded continuously for 25 min with an evaporimeter. The differences between the surfactants were statistically significant (Friedmans test p<0.01). SLS and the A/ N mix revealed significant differences compared to the other compounds (p<0.05), both in decay constants and in values recorded at the beginning and at the end of the decay curve. The study suggests a mechanism for the high irritant potential of sodium lauryl sulphate compared lo other surfactants: sorbitan monolaurate and benzalkonium chloride seem lo influence (at the concentrations tested) to a lesser extent the water‐holding capacity of the stratum corneum. The clinical and biological relevance of these observations requires long‐term clinical correlations with final product use tests.

IN VIVO TRANSCUTANEOUS PENETRATION OF NICOTINATES AND SENSITIVE SKIN

Proclivity to develop irritant reactions and transcutaneous penetration of nictitates has been investigated in 20 subjects of both sexes, divided into reactors and nonreactors on the basis of the responses to irritant stimuli. 1% sodium knurly soleplate (patch application for 24 h) and 5% lactic acid in aqueous solutions were used to feted chemical and sensory (subjective) irritation. The vasodilatation induced was measured using chromameter for 1 h after tropism application of the chemical. The area‐under‐the‐curve response and the peak response were used to assess the in vivo penetration of ruddy nicotinate (10 mM in aqueous solution). Significant differences were found between reactors and non‐reactors. Non‐reactors showed a significantly decreased area‐under‐the‐Curve response and peak response to methyl nicotinate compared to reactors. Nicotinate‐induced vasodilatation has been used as a model to study transcutaneous penetration of chemicals; the correlation between increased penetration of nicotinates and skin hyperreactivity to irritant substances may suggest an increased transcutaneous penetration of water‐soluble chemicals in individuals with sensitive skin.

In vivo tretinoin‐induced changes in skin mechanical properties

Topical tretinoin has been reported as having anti‐aging effects on photodamaged skin. The purpose of this study was to evaluate tretinoin‐induced changes in the mechanical properties of the skin of 18 patients (aged 39±8 years) after 4 months of treatment with topical 0.05% tretinoin on one forearm and a placebo base cream on the other. The biomechanical skin parameters investigated were elasticity, extensibility and hysteresis and data were normalized for skin thickness. A slight but non‐significant increase of skin elasticity was detected in the tretinoin‐treated sites using low‐stressing forces (1·2 × 104 Nm−2) and at higher loads (3·8 × 104 Nm−2), the increase in skin elasticity was significant (P<0·01). This improved skin elasticity was dependent on the increased collagen resulting from topical tretinoin and the replacement of elastotic material. However, topical tretinoin treatment did not improve the responses mediated by elastic fibres.

Skin Bioengineering in the Noninvasive Assessment of Cutaneous Aging

Cutaneous changes induced by aging can be quantified and monitored noninvasively by means of bioengineering tools. Skin elasticity, hydration, skin blood flow and skin surface pattern show age-related changes reflecting the damage of cutaneous structures involved. Impairment and degeneration of elastic and collagen networks are responsible for the progressive decrease in skin elasticity recorded during aging. Reduction in blood flow and water supply with probably defective stratum corneum binding result in reduced stratum corneum water content and transepidermal water loss. Morphological changes such as increased skin roughness, pigmentation and alteration of skin surface pattern appearing from the age of 30 years onwards may be investigated at a subclinical level allowing the detection of early signs of aging.

Bullous lesions in acrodermatitis enteropathica. Histopathologic findings regarding two patients.

Acrodermatitis enteropathica (AE) is an autosomic recessive disorder affecting early infancy. Two cases of infantile AE with low plasma zinc levels are reported in which unusually prominent bullous and vesicobullous lesions were seen on the hands and feet, in addition to the more typical erythematous and scaly patches. Both psoriasiform and bullous lesions responded dramatically to oral zinc-sulfate supplementation. The histopathologic features of the bullous lesions of AE have not previously been fully examined. Histologically, the bullous lesions were characterized by intraepidermal vacuolar changes with massive ballooning, leading to intraepidermal vesiculation and blistering, with prominent epidermal necrosis and with no acantholysis. The bullous lesions did not arise on erythematous patchy lesions, but developed ex novo on unaffected skin. The histopathologic differential diagnosis with other bullous conditions is discussed.

FLAGELLATE DERMATITIS AFTER BLEOMYCIN : A HISTOLOGICAL AND IMMUNOHISTOCHEMICAL STUDY

A case of flagellate dermatitis after administration of bleomycin is reported in a patient with Hodgkins disease. Histopathological and immunohistochemical analysis revealed a drug-induced skin toxic reaction rather than a lymphomatous infiltrate. Pigmentary changes observed after the early erythematous eruption were due to a postinflammatory effect.

Effects of fluid volume changes during hemodialysis on the biophysical parameters of the skin.

Water plays an important role in maintaining skin suppleness and elasticity. We used hemodialysis as a model to investigate the effects on biophysical properties of the skin induced by removal of fluids and water from the body. The following parameters have been investigated before and immediately after a hemodialysis session: body weight, skin elasticity and distensibility, skin hydration, transepidermal water loss (TEWL) and skin thickness. A significant decrease was recorded after treatment in body weight, skin thickness (p < 0.01) and skin elasticity (p < 0.01). Significant linear correlations were found between stratum corneum water content, skin distensibility and TEWL. The data reveal that rapid removal of body fluids influences skin biophysical properties: early changes in skin thickness and ground substance occur in the dermis and affect mechanical properties of the skin. The decrease in water content in the upper layers of the skin occurs at a later stage and influences skin hydration rather than TEWL. This model is a useful tool to investigate water kinetics through the skin.

Clinical trial of the efficacy and safety of oral etretinate with calcipotriol cream compared with etretinate alone in moderate-severe psoriasis.

BACKGROUND The aim of this clinical trial was to assess the efficacy and safety of calcipotriol cream associated with oral etretinate compared with etretinate alone in the treatment of moderate-severe psoriasis. METHODS This controlled multicenter trial, within patients (hemiparts), enrolled 86 in- or out-patients (62 males, 24 females), mean (+/-SD) age 57.1 +/- 14.2 years, with psoriasis vulgaris on both sides of the body, and mean (+/-SE) baseline PASI score (Psoriasis Area and Severity Index) 30.7 +/- 0.9. All patients took oral etretinate 50 mg/day and applied calcipotriol cream (50 microg/g) on one half of their body twice a day. Treatment was continued for 9 weeks, and patients were seen every 3 weeks. RESULTS At the end of the first 3 weeks the PASI score indicated a significant clinical difference between the two sides of the body (P < 0.001, ANOVA), with a reduction of 50.7% in the score for the calcipotriol-treated half, compared with a 39% reduction for the untreated half. By the 9th week of treatment the PASI score was 81.4% lower on the treated half, and 70.3% on the untreated side (P < 0.001, ANOVA). CONCLUSIONS These findings suggest that patients with moderate-severe psoriasis might benefit from treatment with etretinate plus calcipotriol, with the aim of achieving a faster response and an overall smaller total dose of etretinate.

The dermatological spectrum of Turner syndrome

Turner syndrome, characterized by monosomy of X chromosome, has a peculiar phenotype, including short stature, sexual infantilism, cardiovascular, renal, skeletal and skin abnormalities (in particular melanocytic naevi and skin appendage abnormalities). Fifty‐four patients affected by Turner syndrome were investigated. The skin and adnexal changes of Turner syndrome patients were analysed and their frequency was correlated with two karyotype groups (45, X and mosaicism group). A wide spectrum of skin findings was observed in Turner syndrome; in particular melanocytic naevi and pterygium colli were the most frequent findings. Pterygium colli was more frequent in patients with X monosomy than in those with other karyotypes (P < 0.05). The frequency of congenital/congenital‐naevus‐like naevi (CN/CNLN) and acquired melanocytic naevi (AN) (81.6%) was higher in Turner syndrome subjects, independently of their karyotype, than in the general Caucasian population. However, there was an unexpectedly high frequency of ichthyotic changes, café‐au‐lait spots and halo naevi. Hypertrichosis, nail changes and keloid formation were also seen. No significant correlation was found between these dermatological findings and the two karyotype groups considered.