Skin susceptibility of atopic individuals

[Predictive factors of polysensitization to contact allergens: study conducted at the Dermato-Allergology Unit of the Farhat Hached University Hospital in Sousse, Tunisia]

Introduction

polysensitization is often defined as sensitization to three or more contact allergens. The objectives of our study were to determine the prevalence of polysensitization to allergens patch test and to analyze the factors associated with allergen polysensitization of the European Standard Battery in comparison with cases of oligosensitization.

Methods

this is a retrospective descriptive cross-sectional study that included all patients who had undergone patch tests at the Department of Dermato-Allergology of the Department of Occupational Medicine of University Hospital Center Farhat Hached in Sousse spread over 10 years from January 1, 2009 to December 31, 2018.

Results

in total, we collected 464 cases of contact dermatitis during the study period. The average age of patients was 38.93 ± 12.52 years with a slight female predominance (52.8% of cases). Among all the patients who consulted during the study period (832 patients), 133 patients had positive reactions to 3 or more allergens 16% of patients. Concerning, the associations of the most frequently noted allergens were those of triplet (chromium, cobalt, and nickel) in 15 patients and triplet (mercaptobenzothiazole, thiuram mix, and IPPD) in 7 cases. The predictive factors of polysensitivity were the personal history of leg ulcers; the site of the lesions in the thorax and the erythematous squamous and dyshidrotic appearance of the lesions.

Conclusion

this phenomenon is frequent polysensitization, and close collaboration between dermatologists and occupational physicians to prevent this type of multiple allergies through better management of personal and also professional risk factors.

Infant lung function and early skin barrier impairment in the development of asthma at age 3 years

BACKGROUND

Largely unexplored, we investigated if lower lung function, impaired skin barrier function by transepidermal water loss (TEWL), eczema, and filaggrin (FLG) mutations in infancy were associated with asthma in early childhood.

METHODS

From the factorially designed randomized controlled intervention study PreventADALL, we evaluated 1337/2394 children from all randomization groups with information on asthma at age 3 years, and at age 3 months either lung function, TEWL, eczema, and/or FLG mutations. Lower lung function was defined as the time to peak tidal expiratory flow to expiratory time (tPTEF /tE ) <0.25, and skin barrier impairment as a high TEWL >9.50 g/m2 /h. Eczema was clinically observed, and DNA genotyped for FLG mutations. Asthma was defined as asthma-like symptoms (≥3 episodes of bronchial obstruction) between age 2-3 years as well as a history of doctor-diagnosed asthma and/or asthma medication use. Associations were analyzed in logistic regression models, presented with adjusted ORs (aOR) and 95% confidence intervals (CI).

RESULTS

Lower lung function and skin barrier impairment were associated with asthma in general; aOR (95% CI) 5.4 (2.1, 13.7) and 1.6 (1.1, 2.5), while eczema and FLG mutations were associated with asthma in children with atopic dermatitis or allergic sensitization only. Stratifying for sex, the risk of asthma was only increased in boys with lower lung function; aOR (95% CI) 7.7 (2.5, 23.6), and in girls with FLG mutations; aOR (95% CI) 3.5 (1.5, 8.2).

CONCLUSION

Lower lung function and impaired skin barrier function in infancy may increase the risk of asthma at age 3 years.

Skin Barrier Function and Infant Tidal Flow-Volume Loops-A Population-Based Observational Study

Background: The relationship between the skin barrier- and lung function in infancy is largely unexplored. We aimed to explore if reduced skin barrier function by high transepidermal water loss (TEWL), or manifestations of eczema or Filaggrin (FLG) mutations, were associated with lower lung function in three-month-old infants. Methods: From the population-based PreventADALL cohort, 899 infants with lung function measurements and information on either TEWL, eczema at three months of age and/or FLG mutations were included. Lower lung function by tidal flow-volume loops was defined as a ratio of time to peak tidal expiratory flow to expiratory time (tPTEF/tE) <0.25 and a tPTEF <0.17 s (<25th percentile). A high TEWL >8.83 g/m2/h (>75th percentile) denoted reduced skin barrier function, and DNA was genotyped for FLG mutations (R501X, 2282del4 and R2447X). Results: Neither a high TEWL, nor eczema or FLG mutations, were associated with a lower tPTEF/tE. While a high TEWL was associated with a lower tPTEF; adjusted OR (95% CI) 1.61 (1.08, 2.42), the presence of eczema or FLG mutations were not. Conclusions: Overall, a high TEWL, eczema or FLG mutations were not associated with lower lung function in healthy three-month-old infants. However, an inverse association between high TEWL and tPTEF was observed, indicating a possible link between the skin barrier- and lung function in early infancy.

A green synthesis approach toward large-scale production of benzalacetone via Claisen-Schmidt condensation

Claisen–Schmidt (CS) condensation between acetone and benzaldehyde with NaOH as the catalyst is a well-recognized pathway for the synthesis of benzalacetone (BA). However, this process is compromised by a side reaction, i.e., a second CS reaction between benzaldehyde and the BA product. In this work, we designed a stirring-induced emulsion synthesis technique for the cyclic and scaling-up production of BA with 99 ± 1% selectivity, without the use of surfactants. In this approach, the water-soluble acetone and NaOH were separated from the oil-soluble benzaldehyde by the organic–aqueous phase interface, such that the CS condensation could only be executed at the liquid interface. The just-formed BA molecules diffuse to the interior of the oil solvent, where any subsequent CS post-reaction is rendered negligible, owing to the absence of NaOH. The oil phase containing the BA molecules can be easily separated from the aqueous solution by stopping stirring and undisturbed standing, allowing for a large-scale production protocol. As a proof of concept, over 1 kg of BA was produced in the laboratory with high yield and purity.

A stirring-induced emulsion system enables 99% selectivity to the mono-condensation product of a Claisen–Schmidt reaction. The system showed good cyclic performance and can be easily scaled up to kilogram-level for the production of benzalacetone.

Challenging a paradigm: skin sensitivity to sodium lauryl sulfate is independent of atopic diathesis

BACKGROUND

Sodium lauryl sulfate (SLS) is the best-studied detergent in irritant contact dermatitis. In atopic dermatitis, the two major pathophysiological abnormalities concern skin barrier function and regulation of cutaneous immune responses. The probability of atopic skin diathesis can be assessed by comprehensive analysis of patient history, as well as clinical and laboratory findings, resulting in the Erlangen Atopy Score (EAS).

OBJECTIVES

To investigate the impacts of (i) atopic skin diathesis according to the EAS and (ii) the physician-assessed diagnoses 'atopic dermatitis', 'allergic rhinitis' and 'allergic asthma' on SLS skin reactions.

METHODS

This is a retrospective analysis of data from 2030 consecutive patients patch tested with SLS (0·25% aqueous) from two tertiary referral centres in Germany, from 2008 to 2014.

RESULTS

Patients with a high probability of atopic skin diathesis showed no significant increase in positive SLS reactions compared with patients without atopic skin diathesis (14·2% vs. 16·8%). The grading of positive SLS skin reactions (1-4) revealed no differences in patients with or without atopic skin diathesis. Furthermore, diagnoses of atopic dermatitis, allergic rhinitis or allergic asthma had no impact on positive SLS skin reactions in multivariate logistic regression analysis.

CONCLUSIONS

We found no association of increased skin irritability to SLS with atopic skin diathesis, atopic dermatitis, allergic rhinitis or allergic asthma in a large patient cohort. It therefore seems that the test of skin irritability with SLS, which is currently common practice in many centres, does not allow prediction of susceptibility to irritant eczematous inflammation in atopic vs. nonatopic individuals. What's already known about this topic? Irritant contact dermatitis and atopic skin diathesis share impaired skin barrier function as a pathophysiological pattern. Sodium lauryl sulfate (SLS) is tested at 0·25% aqueous as an irritant control in patch testing, and hence the results might be affected by atopic skin diathesis. What does this study add? Challenging a long-standing paradigm, we found no association of increased reactivity to SLS patch tests in individuals with atopic skin diathesis, atopic dermatitis, allergic rhinitis or allergic asthma in a large patient cohort. Thus, irritant control testing with SLS, which is useful in interpreting doubtful allergen patch test results, does not depend on individual atopy status.

Dry skin manifestations in Sjögren syndrome and atopic dermatitis related to aberrant sudomotor function in inflammatory allergic skin diseases

We have reported characteristic cutaneous manifestations of Sjögren syndrome (SS) with special references to autoimmune anhidrosis or hypoidrosis and related mucocutaenous manifestations in addition to annular erythema or cutaneous vasculitis. Although significance of cutaneous manifestations of SS has been gradually recognized in rheumatologists, sudomotor function has not been fully evaluated and recognized in the diagnosis of SS except for dermatologists. SS is a relatively underestimated collagen disease in contrast to SLE, systemic sclerosis, or dermatomyositis, special care should be needed not to make misdiagnosis of SS when we see the patients with common skin disease such as, drug eruption, infections skin disease or xerosis in the daily practice. In contrast to pathomechanisms of dry skin observed in SS, we recently reported that reduced sweating function and dry skin seen in atopic dermatitis (AD) are mediated by histamine or substance P, those are usually restored to normal levels after improvement of the dermatitis by topical corticosteroid ointment with or without oral anti-histamine. Therefore, xerotic skin lesions seen in SS and AD might be attributable to different pathomechanisms with similar dry skin manifestations. We recently reported that SS promotes dry skin when complicated with AD possibly due to acceleration of hypoidrosis. In this review, we would like to summarize our recent understanding of regulatory mechanism of impaired sweating function in allergic inflammatory skin diseases by introducing clinical presentations of AD/SS overlap cases as the model of hypoidrotic inflammatory skin diseases.

Atopic dermatitis results in intrinsic barrier and immune abnormalities: implications for contact dermatitis

Atopic dermatitis (AD), as well as irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD), are common skin diseases. These diseases are characterized by skin inflammation mediated by activated innate immunity or acquired immune mechanisms. Although AD, ICD, and ACD can be encountered in pure forms by allergists and dermatologists, patients with AD often present with increased frequency of ICD and ACD. Although a disturbed barrier alone could potentiate immune reactivity in patients with AD through increased antigen penetration, additional immune mechanisms might explain the increased susceptibility of atopic patients to ICD and ACD. This review discusses cellular pathways associated with increased skin inflammation in all 3 conditions and presents mechanisms that might contribute to the increased rate of ICD and ACD in patients with AD.

Four cases of atopic dermatitis complicated by Sjögren's syndrome: link between dry skin and autoimmune anhidrosis

We report four adult cases of atopic dermatitis (AD) complicated by Sjögren's syndrome (SS). The patients fulfilled diagnostic criteria for AD and SS. All cases showed persistent itchy dry skin and eczematous lesions complicated by sicca symptoms including dry eyes and dry mouth with moderate joint pain. One case manifested annular erythema and another manifested widespread discoid erythema. To investigate the underlying cause of dry skin in these cases, sweating function was evaluated using a quantitative sudomotor axon reflex test (QSART) in which the axon reflex is stimulated by acetylcholine iontophoresis. The sweating latency time was significantly prolonged in eczematous skin of AD and AD/SS compared to normal controls. Axon reflex (AXR) sweat volume was also significantly reduced in AD (normal and eczematous skin) and AD/SS (normal and eczema) compared to normal control. In contrast, the direct sweat volume of lesional or non-lesional AD skin induced by direct stimulation with acetylcholine was only slightly reduced compared to that in normal controls, but not in SS and lesional skin of AD/SS patients. These results suggest that the impaired sweat response in AD is attributable to an abnormal sudomotor axon reflex, which is accelerated and modulated when complicated by SS resulting in dry skin in the present cases.

Barreira cutânea na dermatite atópica

O estudo da barreira cutânea e de suas propriedades ganhou impulso a partir da década de 60, com estudos que apontaram sua resistência de forma isolada e suas propriedades com relação à permeação cutânea. Paralelamente, a descrição dos corpos de Odland auxiliou a compreensão da manutenção da estabilidade da camada córnea. O modelo brick & mortar, em que os corneócitos são os tijolos e o cimento são os lipídeos intercelulares, é o mais aceito, até o momento. Atualmente, há evidências consistentes de que o estrato córneo é uma estrutura metabolicamente ativa e exerce funções adaptativas. A barreira cutânea também tem um papel na resposta inflamatória, com ativação de melanócitos, angiogênese e fibroplasia, cuja intensidade depende, basicamente, da intensidade da agressão. As anormalidades da barreira cutânea da dermatite atópica são clinicamente observáveis pela presença de pele seca, achado muito frequente e significativo, que constitui parâmetro iagnóstico e de acompanhamento. O grau de hidratação da camada córnea, assim como a perda de água transepidérmica (transepidermal water loss - TEWL), estão relacionados com o grau de dano à barreira, constituindo parâmetros biofísicos que permitem acompanhar os pacientes de maneira não invasiva e com maior grau de sensibilidade.

Dendritic cells express hematopoietic prostaglandin D synthase and function as a source of prostaglandin D2 in the skin

Prostaglandin D2 (PGD2), an arachidonic acid metabolite, has been implicated in allergic responses. A major source of PGD2 in the skin is mast cells that express hematopoietic PGD synthase (H-PGDS). In this study, we show the expression of H-PGDS in human dendritic cells (DCs) and the regulatory mechanisms by which DCs produce PGD2. We detected H-PGDS in epidermal Langerhans cells, dermal DCs, plasmacytoid DCs, and myeloid DCs. Monocyte-derived DCs rapidly secreted PGD2 when stimulated with the calcium ionophore A23187. More importantly, pretreatment of monocyte-derived DCs with PMA (phorbol 12-myrisate 13-acetate) synergistically enhanced the rapid PGD2 secretion induced by A23187, whereas PMA alone did not induce PGD2 secretion. Lipopolysaccharide (LPS) reduced H-PGDS expression, but interferon-gamma followed by LPS induced significant PGD2 production in a delayed time course at 6 hours. This effect was associated with inhibition of LPS-induced H-PGDS reduction. Interestingly, an irritant compound, SDS, also induced a rapid PGD2 release. PGD2 synergistically enhanced CCL22/macrophage-derived chemokine synthesis in interferon-gamma-treated human keratinocytes. In addition, bone marrow-derived DCs from wild-type mice stimulated lymph node cells to produce higher amounts of interleukin-17 than did DCs from mice lacking the H-PGDS gene. Thus, DCs could be an important source of skin PGD2 and may mediate or regulate skin inflammation by releasing PGD2 in response to various stimuli, contributing to the innate and/or acquired immune responses.

Characterization of the polysensitized patient: a matched case-control study

BACKGROUND

Polysensitization ( >or= 3 contact allergies) may be regarded as a special entity in patients with contact allergies. However, this group of polysensitized patients is poorly characterized. Filaggrin mutations are associated with atopic eczema and lead to impaired skin barrier which may predispose to contact allergy. Therefore, it is of interest to consider atopic eczema and contact allergies, especially in patients with multiple allergies.

OBJECTIVE

To characterize polysensitized patients regarding occurrence, duration and course of dermatitis, and examine potential risk factors for polysensitization, including atopic eczema.

METHODS

A questionnaire case-control study of 562 polysensitized and 1124 single/double-sensitized individuals was performed.

RESULTS

The results show that 45% of polysensitized and 31% of single/double-sensitized patients had or had had atopic eczema, and atopic eczema was identified as a risk factor for polysensitization. Patients with leg ulcer constituted only a minor part of the polysensitized group and leg ulcers were not identified as a risk factor for polysensitization in this study. The influence of contact allergies on duration and course of disease diverged between the group of patients with atopic eczema and the group without atopic eczema.

CONCLUSION

Patients with atopic eczema were overrepresented in the group of polysensitized patients and polysensitized patients should be viewed in the light of occurrence or lack of atopic eczema.

Putative neuronal mechanisms of sensitive skin

According to epidemiological studies, up to 50% of adults report facial sensitivity with various distinctive symptoms, such as prickling, burning, tingling, pain or itching. This is termed sensitive skinand represents a syndrome of physiological reactions rather than a disease entity. In this review, we discuss the currently available literature on this syndrome and describe the possible underlying neuronal pathomechanisms. The sensory receptors expressed on unmyelinated nerve fibres and keratinocytes involved in nociception, such as TRPV1 and endothelin receptors, are hypothesized to play a role in the induction of sensitive skin. Furthermore, we discuss the role of neurotrophins and the influence of stress on sensitive skin.

Allergic contact dermatitis among maintenance and clerical workers in a military population

Contact dermatitis is one of the leading causes of occupational morbidity and absenteeism and has become an intolerable cause of missed workdays and health problems in the Israeli military. The aim of this study was to determine the rate of contact dermatitis in maintenance and clerical workers, the common allergens causing it, and the background of atopy in the subjects in order to design preventive measures. Medical records of all recruits to the Israel Defense Forces from 2000 to 2003 were reviewed for contact dermatitis. The 102 cases found were further assessed for job assignment, atopic background, and allergens. Of the 102 cases, 60 had irritant contact dermatitis and 42 had allergic contact dermatitis, of which 33 (78.6%) were maintenance workers, mainly mechanics. 13 soldiers in the maintenance job category (39%) and 2 soldiers in the clerical group (22.2%) had atopic background. There were 55 positive reactions in patch tests, 25 of them to oil and cooling fluids, with 14.5% attributed to methylchloroisothiazolinone/methylisothiazolinone) (Kathon CG). Atopy was found to be a risk factor for allergic contact dermatitis in our study and should be screened for in job assignment procedures in the military. Oil and greases contain significant allergens, especially their preservatives.

Impaired skin barrier and atopic diathesis in perioral dermatitis

BACKGROUND

Perioral dermatitis (PD) is a common dermatological disease whose aetiology and pathogenesis remain speculative. We investigated skin barrier function and various markers of the atopic diathesis to elucidate their impact on the development of perioral dermatitis.

PATIENTS AND METHODS

Forty patients (24 to 69 years of age) with PD were evaluated. Transepidermal water loss was measured in three regions of the face (lateral chin, perinasal cheek and side of the nose) and the patients were assessed for clinical criteria for atopy. Prick tests were performed, and specific IgE against a mixture of aeroallergens (CAP SX1) was measured. The control group consisted of 62 individuals (20 to 68 years of age) without a history of PD or active disease.

RESULTS

Transepidermal water loss was significantly increased (P < 0.001) on all regions of the face in the patient over the control group. Significantly (P < 0.001) higher values were also found for the patient group regarding history (52.5% vs. 17.7%) and clinical signs of atopic diathesis (> or = 4 features: 72.5% vs. 0%), prick test reactivity (> or = 2 reactive prick tests: 60% vs. 12.9%), and specific IgE against aeroallergens (CAP SX1 classes > or = 2: 60.0% vs. 17.7%).

CONCLUSIONS

Our findings emphasize the relevance of impaired skin barrier function as a pathogenic factor in the causation of perioral dermatitis. The susceptibility of atopic skin to irritants increases as soon as the skin becomes eczematous. Therefore, we propose that atopic diathesis serves as an intensifier, supporting development and continued presence of perioral dermatitis after nonspecific irritant mechanisms have induced impaired skin barrier function.

Periokulare Dermatitis. Periocular dermatitis

BACKGROUND

Perioral dermatitis paradoxically sometimes spares the entire perioral region. There may be isolated periocular involvement (periocular dermatitis).

PATIENTS/METHODS

The records of 23 patients with only periocular dermatitis were reviewed with respect to the following parameters: clinical findings, history of atopy, topical facial treatment, prick and patch tests, CAP-SX1, previous treatment, time to healing and relapses. 23 patients with no history of periocular dermatitis were matched for age and sex (case-control study).

RESULTS

The predominant clinical finding in the affected group was micropapules primarily in the lateral corner of the eye and lower eyelid. The groups differed significantly (p < 0.05) with regard to the history of atopic diseases and reactive prick tests. 22 patients regularly used face-care or eye-care products. These patients did not differ significantly from the control group with regard to frequency and type of product used. 6 patients had been previously treated with topical corticosteroids. The time to healing was 2-8 weeks (median: 4 weeks).

CONCLUSIONS

Periocular dermatitis is a variation on perioral dermatitis, where-by similar pathogenetic factors are observed. The elimination of topical corticosteroids and the gradual reduction of skin-care products regularly lead to clearing of the condition.

Basal electrical impedance in relation to sodium lauryl sulphate-induced skin reactions - a comparison of patients with eczema and healthy controls

BACKGROUND

Identification of subjects at risk for contact dermatitis by screening tests is desirable in order to adjust the preventive measures to individual skin susceptibility. The present study aimed to examine the effects of basic physiological features, such as baseline electrical impedance (IMP) and transepidermal water loss (TEWL), on reactivity to sodium lauryl sulphate (SLS).

METHODS

On the basis of two previous studies, we re-evaluated the experimental irritant skin reactions (50 microL of 2% SLS in large Finn Chambers for 24 h) on the volar forearms of 29 patients with eczema and 19 healthy controls.

RESULTS

We found definite differences in the baseline values of IMP, between the patients and the controls. Moreover, patients with eczema showed higher TEWL and lower MIX values on day 3 after exposure to SLS, which may indicate differences in SLS reactivity. After the study, the biophysical parameters of the eczema patients did not return to baseline, which suggests that their skin heals more slowly than that of normal subjects.

CONCLUSIONS

Our findings indicate that the IMP technique may help to 'detect' chemically vulnerable skin. However, more studies are needed to determine the value of the basal electrical impedance parameters in assessing the risk of developing irritant contact dermatitis.

Patch-test reaction patterns in patients with a predisposition to atopic dermatitis

Patients with a predisposition to atopic dermatitis often need to be patch tested in order to detect possible contact sensitization. However, it is unknown whether immunologic or other peculiarities of atopic skin are related to altered patch-test reaction patterns. Our study was aimed at answering this question, because patch-test reaction patterns are of considerable practical importance in the reading and interpretation of patch tests. Therefore, we compared patterns of patch-test reactions in patients with a predisposition to atopic dermatitis and in control patients matched for sex, age, reason for testing and test centre. Patch-test results from 9 centres (2322 patients with a disposition to atopic dermatitis and 2126 matched controls) were evaluated retrospectively. All patients were tested with nickel sulfate, fragrance mix, potassium dichromate, lanolin alcohol, formaldehyde and mercury ammonium chloride. Patch tests applied for 1 day with readings on days 1, 2 and 3 were evaluated in order to cover the early phase of the reactions. Not unexpectedly, we found that, compared to the matched controls, patients with a predisposition to atopic dermatitis tended to have more doubtful and irritant reactions on day 1. As a new observation, it turned out that they had less reactions of crescendo pattern and more strong reactions on day 3. All these differences were slight/insignificant. A higher skin irritability in patients with a predisposition to atopic dermatitis is a likely explanation. In conclusion, standard methods for patch testing can be applied in patients with a predisposition to atopic dermatitis, but minor differences in reaction patterns should be considered.

The association between ambient air conditions (temperature and absolute humidity), irritant sodium lauryl sulfate patch test reactions and patch test reactivity to standard allergens

To support the decision as to whether erythematous patch test reactions to allergens are irritant or allergic, sodium lauryl sulfate (SLS, 0.5% in water) has been added to the standard patch tests since July 1996 in the Dortmund Department of Dermatology. Data on 1600 patients patch tested up until June 2001, as well as standardized data on ambient temperature and humidity obtained by the German Meteorological Service, were included in a logistic regression analysis taking age, sex and atopy as potential confounders into account. The pattern of association was heterogeneous: while doubtful reactions to nickel sulfate were significantly associated with dry/cold weather conditions, but not with SLS reactivity, the opposite was observed for lanolin alcohol, benzocaine and Myroxylon pereirae resin (balsam of Peru). Doubtful reactions to other allergens, namely formaldehyde, fragrance mix or p-phenylenediamine, were associated with both factors. For several other allergens of the standard series, no distinct, significant pattern could be discerned. In conclusion, meteorological conditions and SLS reactivity independently contribute information on individual irritability at the time of patch testing, and both should be considered.

Cutaneous response to irritants

We evaluated the role of pre-existing dermatitis in the response to irritants by patch testing the skin of 40 healthy volunteers and the uninvolved skin of 480 subjects for 2 days. These latter were affected by active atopic dermatitis, psoriasis, eczema with positive and negative patch test reactions, urticaria and generalized pruritus. A first panel containing 15 micro L of aq. solutions of disodium laureth sulfosuccinate (NaLSS) 5% and 10%, potassium cocoate (KCC) 5%, potassium oleate (KOL) 5%, zinc coleth sulphate (ZnCS) 5%, sodium mireth sulphate (NaMS) 5%, sodium cocoamphoacetate (NaCCAA) 3% and 5%, was simultaneously applied to 1 site on the upper back. The results, scored by visual assessment, were compared to those observed when testing on the opposite side a second panel containing 15 micro L of aq. solutions of 3 well-known irritants, benzalkonium chloride (BAK) 1%, sodium lauryl sulphate (SLS) 1%, and dimethylsulphoxide (DMSO) 10%. Whilst the substances of the first panel and DMSO gave, on the whole, a scarce number of positive responses in all the tested groups, more evident differences in number, percent and mean intensity of the positive responses to BAK and SLS were found between the different groups. Although some of them seemed statistically significant, when the same values were evaluated by means of chi2 and Student t-test, they did not differ in a statistically significant way from the values found in healthy subjects. The results of this study seem to indicate that the substances of the first panel have a chemical structure that makes them quite safe in real-life conditions. In contrast, BAK and SLS have chemical properties that condition the number and intensity of the responses, making the role exerted by the pre-existing dermatosis quite marginal. In particular, there is no proof that the healthy skin of active atopic subjects is the most susceptible to the irritating effects of the tested substances.

Occurrence of patchy parakeratosis in normal-appearing skin in patients with active atopic dermatitis and in patients with healed atopic dermatitis: a cause of impaired barrier function of the atopic skin

It remains unclear whether an impaired barrier function often seen in areas of normal-appearing skin in patients with active atopic dermatitis (AD) is primary event in nature or secondary to subclinical eczematous change. We then attempted to evaluate the barrier function of normal-appearing skin in both active and healed AD patients, and as well as see whether a subclinical eczematous change exists or not in the normal-appearing skin using a non-invasive method. Transepidermal water loss (TEWL) measurement and exfoliative cytology method for corneal layer were applied in 153 AD patients who have active skin lesions and 29 individuals with completely healed AD for at least 5 years and 40 normal individuals. The TEWL of normal-appearing skin in severe, moderate and mild AD cases was 10.5+/-2.9, 8.3+/-2.4 and 7.3+/-2.1 g/m2 per h, respectively. The TEWL values in severe and moderate cases were significantly higher than the normal controls (6.2+/-1.6 g/m2 per h). However, the TEWL was not deranged in patients with completely healed AD. An exfoliative cytology examination of corneal layer disclosed that patchy parakeratosis appeared in normal-appearing skin in severe, moderate and mild AD cases at a rate of 42, 29 and 19%, respectively. However, no patchy parakeratosis was recognized in patients with completely healed AD. The occurrence of patchy parakeratosis in normal-appearing skin in patients with active AD suggests that an impaired barrier function often seen in normal-appearing skin in AD patients is secondary to subclinical eczematous change in the area.

Impaired sweating function in adult atopic dermatitis: results of the quantitative sudomotor axon reflex test

BACKGROUND

Impaired sweating is thought to be a cause of barrier dysfunction in atopic dermatitis (AD).

OBJECTIVES

To examine the sweating function in AD in a quantitative manner.

METHODS

We investigated the sweating response of lesional and non-lesional skin of adult patients with AD by a quantitative sudomotor axon reflex test in which the axon reflex is stimulated by acetylcholine iontophoresis. Sweat volume on the volar aspect of the forearm was measured in 18 adult patients with AD and in 40 non-atopic controls; five patients with Sjögren's syndrome were also studied as disease comparators. We also evaluated the sweating function in four AD patients after topical corticosteroid therapy. Latency time, direct (DIR) sweat volume and axon reflex-mediated indirect (AXR) sweat volume were the variables studied.

RESULTS

The latency time in AD patients was significantly prolonged and AXR sweat volume significantly reduced compared with those in non-atopic control subjects. The latency time and AXR sweat volume of lesional AD skin were significantly more prolonged and reduced, respectively, than those of non-lesional skin. In contrast, the DIR sweat volume of lesional or non-lesional AD skin induced by direct stimulation with acetylcholine was only slightly reduced when compared with that in non-atopic controls. Latency time and sweat volumes of lesional and non-lesional AD skin improved after topical corticosteroid therapy.

CONCLUSIONS

These results suggest that the impaired sweat response in AD is attributable to an abnormal sudomotor axon reflex, which is reversed by topical corticosteroid administration.

Allergic contact dermatitis elicitation thresholds of potent allergens in humans

Literature scoured for human allergenicity to individual chemicals yields a limited number of potent sensitizers, which can be classified in four categories: metals, botanicals, biocides and miscellany. Potency is defined as strong for substances eliciting eczematous reactions to patch concentrations of 500 ppm (parts per million) or less in sensitized individuals. Most data encountered stem from studies conducted on dermatology patients tested routinely for hypersensitivity; only few data have been generated by systematic serial dilution testing.

The new topical ascomycin derivative SDZ ASM 981 does not induce skin atrophy when applied to normal skin for 4 weeks: a randomized, double-blind controlled study

BACKGROUND

SDZ ASM 981 is a selective inhibitor of inflammatory cytokines released from T lymphocytes and mast cells, which has been developed for the treatment of inflammatory skin diseases.

OBJECTIVES

In the present study, the atrophogenic potential of SDZ ASM 981 1% cream in humans was compared with that of medium and highly potent topical steroids, and vehicle.

METHODS

Four different preparations, SDZ ASM 981 1% cream, the corresponding vehicle of SDZ ASM 981 1% cream, betamethasone-17-valerate 0.1% cream and triamcinolone acetonide 0.1% cream, were applied to the volar aspect of the forearms of 16 healthy volunteers, twice daily, 6 days a week, for 4 weeks. Skin thickness was evaluated by ultrasound examination, clinical signs of atrophy by stereomicroscopy, and epidermal thickness was assessed by histology.

RESULTS

Both topical corticosteroids induced a significant reduction in skin thickness, as compared with SDZ ASM 981 1% cream and vehicle, which were shown to be equivalent. The difference in skin thickness (measured by ultrasound examination) between patients treated with SDZ ASM 981 1% cream and those receiving either of the two topical steroids was significant from day 8 onwards. Histological analysis performed at day 29 showed significant epidermal thinning with topical steroids compared with SDZ ASM 981 1% cream or the vehicle. Conclusion The lack of atrophogenic properties of SDZ ASM 981 1% cream in this short-term study demonstrates its potential as long-term treatment for inflammatory skin diseases, thus overcoming a major drawback of topical steroids. This may also be important for the treatment of children, and sensitive areas of skin, such as the face and skin-folds.

Skin barrier function in patients with completely healed atopic dermatitis

Although it has been well established that the dry skin often seen in patients with atopic dermatitis shows a deranged barrier function, there is no unanimity of opinion as to whether the barrier in normal-appearing skin of patients with the disease is deranged or not. Hence, it remains unclear whether individuals with atopic dermatitis constitution have an intrinsic derangement of skin barrier function or not. To settle this problem, in the present study we examined transepidermal water loss and stratum corneum water content in normal appearing skin of the upper back of 16 patients with completely healed atopic dermatitis who had been free from skin symptoms for 5 years or more, 30 patients with active atopic dermatitis, and 39 healthy subjects. The transepidermal water loss values and the stratum corneum water content values in normal-appearing skin of the completely healed patients were not different from the values in normal controls. These findings indicate that skin barrier function is not disturbed in patients with completely healed atopic dermatitis.