Occupational dermatoses in farmers growing okra (Hibiscus esculentus L.)

By questionnaire survey, 32 out of 52 workers (61.5%) reported previous or current skin diseases from okra cultivation. The sites of skin lesions were mainly the arms, fingers and fingertips. Positive patch test reactions with preparations of okra leaves or immature pods in 111 workers, compared to 63 control subjects, were significantly higher in okra workers than in controls (p less than 0.01), ranging from 9.8 to 30.0%. 37 out of 111 workers (33.3%) were diagnosed as having allergic contact dermatitis (n = 17; 15.3%) and irritant contact dermatitis (n = 18; 16.2%) from okra cultivation.     

Allergic contact dermatitis in shiitake (Lentinus edodes (Berk) Sing) growers

A 42-year-old female shiitake grower was investigated to clarify the etiology of skin lesions which developed during the planting of shiitake hyphae into bed logs. She complained of repeated eczematous skin lesions during the planting season, from March to July, for 10 years. She handled 7,000 pieces of small conic blocks made of beech, with shiitake hyphae attached to their surface, per day, and 300,000 pieces altogether per season. She was positive on patch testing with extracts of shiitake hyphae. In contrast, female shiitake growers with skin lesions associated with work other than planting, and without skin lesions, were negative on patch testing to the hyphae. Moderate allergenicity was observed to extracts of shiitake hyphae in a guinea pig maximization test. These findings indicated the etiology of skin lesions in shiitake growers to be allergic contact dermatitis induced by shiitake hyphae.     

Reduced skin threshold to irritation in the presence of allergic contact dermatitis in the guinea pig

The skin is more susceptible to irritation when an active eczematous process is present. This reduced threshold to irritation occurs in skin distant from the site of the eczematous skin. Data is presented to demonstrate the appearance of irritant dermatitis to lower concentrations of sodium lauryl sulfate during the presence of an allergic contact dermatitis in the guinea pig.     

Augmentation of skin response by exposure to a combination of allergens and irritants - a review

Clinical experimental studies on contact dermatitis (CD) often evaluate the effect of one allergen or one irritant at a time. In real life, the skin is often exposed to more allergens, more irritants or allergens and irritants in combination. This combined exposure may potentially influence irritant effects as well as allergenicity of the substances. Mechanisms for a changed response can be immunological effects or enhanced penetration. Knowledge about the influence on skin reaction of combined exposures may influence skin reactivity and is important for prevention of CD. For allergens, threshold values may be influenced by the presence of other allergens or irritants, and prevention of CD by regulation of threshold values may not be sufficient if this is not taken into account.     

Identification of contact sensitizers by animal assay

Guinea pig testing constitutes the first step in evaluating the allergenicity of new chemicals and products. Some of the most commonly used animal predictive tests are reviewed. The guinea pig maximization test, which is the recommended test method in Sweden, is described in detail and the interpretation of results obtained with this test is discussed. In the guinea pig maximization test the sensitization capacity of a substance is examined by the use of maximized conditions for i he exposure, i.e. the potential ability of the material to induce a contact allergy is determined. The extent to which an allergen causes contact dermatitis in exposed persons depends on the mode of use and various environmental factors.     

Periorbital dermatitis: Causes,differential diagnoses and therapy

Periorbital dermatitis is common and frequently difficult to treat. Patients with periorbital dermatitis often suffer severely because their disease is in such a visible location. Because of the variety of clinical appearance, the differential diagnostic considerations are often difficult. We examined the causes of periorbital dermatitis and compared the data of 88 patients from the Department of Dermatology, University Hospital Erlangen to those of the German IVDK (Information Network of the Departments of Dermatology). Between 1999 and 2004, predominant causes of periorbital dermatitis were allergic contact dermatitis (Erlangen 44 %, IVDK 32 %), atopic eczema (Erlangen 25 %, IVDK 14 %), airborne contact dermatitis (Erlangen 10 %, IVDK 2 %) and irritant contact dermatitis (Erlangen 9 %, IVDK 8 %). Less frequent causes for secondary eczematous periocular skin lesions were periorbital rosacea, allergic conjunctivitis or psoriasis vulgaris. Female gender, atopic skin diathesis and age of 40 years and older were identified as risk factors for periocular dermatitis. Common elicitors of periorbital allergic contact dermatitis were leave‐on cosmetic products (face cream, eye shadow) and eye drops with the usual allergens being fragrances, preservatives and drugs. Exact identification of relevant contact allergens and allergen elimination are essential for successful treatment. Calcineurin inhibitors are the first‐line therapy for facial atopic eczema. They may be also effective in periocular eczematous lesions of other origins although they are not approved for such use.     

An animal model for altering the irritability threshold of normal skin

Theory behind conditioned hyperirritability (autoeczematization) predicts the lowering of the irritation threshold in the presence of a pre-existing dermatitis. We have attempted to develop an animal model that parallels the syndrome seen in man. Groups of 10 guinea pigs were shaved and depilated; irritation thresholds to benzalkonium chloride and trichloroacetic acid were determined using 1 cm diameter open patches. Reactions were scored 24 h later on the basis of erythema and induration. Animals having as little as 1.56 cm2 of skin acutely inflamed with a known irritant had lowered irritation thresholds to the same irritant on normal skin at remote sites (p less than 0.01). Mild irritation of a much larger surface area produced the same effect (p less than 0.01). More extensive, severe dermatitis did not lower the irritation threshold further. Acute dermatitis induced by a contact allergen (DNCB) lowered the irritation threshold of normal skin to the same level as that obtained with irritants (p less than 0.01). Induction of chronic cutaneous ulcers 3-4 cm in diameter lowered the irritation threshold of normal skin to the same point defined by the acute studies (p less than 0.01). These results indicate that an acute irritant or contact dermatitis, as well as chronic skin ulceration, may alter the reactivity of unaffected normal skin to exhibit a heightened response to irritation. This model appears to differ from that seen in humans, in that a more extensive or chronic dermatitis did not further heighten the susceptibility to irritation.     

Hypersensitivity reaction to the ingestion of mango flesh

A 42-year-old woman presented with a hypersensitivity reaction after the ingestion of a small amount of fresh mango gelato. She developed itchy palpable purpuric lesions over her arms, legs, neck and abdomen 4 days after ingestion. The lesions persisted for 5 weeks despite treatment with betamethasone-17 valerate 0.05% ointment and avoidance of mango. Resolution of these lesions was eventually achieved with continuing treatment. The patient denied any prior contact with mango skin but had experienced previous sensitizing reactions to mango flesh. Patch testing was strongly positive to mango skin and mango flesh. Skin-prick testing was negative. This case describes a systemic contact dermatitis to mango flesh, an entity less common than allergic contact dermatitis.     

Topical application of artesunate on guinea pig allergic contact dermatitis

Artesunate is derived from the Chinese medicinal herb qinghao. Many animal studies suggest that systemic artesunate has immunoregulatory activity. We investigated the effect of topical artesunate on contact sensitivity in guinea pigs sensitized with DNCB. Female hairless guinea pigs were used and the contact reaction graded by visual (5 point) score and erythema measured with a color analyzer. Topical artesunate inhibited the elicitation reaction of contact hypersensitivity when given at the 1st and 12th h after challenge ( p < 0.05), but showed no effect when given from day 3 to day I before challenge ( p > 0.05). Artesunate had no effect on toxic (irritant) contact dermatitis from 20% croton oil ( p > 0.05). The results indicate that topical application of artesunate may offer a novel treatment of allergic contact dermatitis and other cutaneous immune-mediated disorders.     

Sites of dermatitis in a patch test population: hand dermatitis is associated with polysensitization

Background  Sites of dermatitis in larger series of contact allergic patients are rarely reported. Increased risk of polysensitization has been linked only to stasis dermatitis and leg ulcers. However, a large proportion of polysensitized individuals may have dermatitis in other skin areas.
Objectives  To examine the site of dermatitis at time of first appearance in contact allergic individuals with special focus on the distribution of dermatitis in polysensitized individuals and to examine if widespread dermatitis is more frequent in polysensitized than in single/double-sensitized patients.
Methods  A matched case–control study was carried out including 394 polysensitized and 726 single/double-sensitized patients who responded to a postal questionnaire. All subjects were recruited from a hospital patch test population.
Results  The hands were the most frequent and the anogenital region was the least frequent skin area affected with dermatitis. Dermatitis on the hands/wrists [odds ratio (OR) 1·58], in the armpits (OR 1·56) and on the back (OR 1·91) was positively associated with polysensitization. The hands were the only skin area with dermatitis which maintained the association to polysensitization in two subpopulations consisting of, respectively, individuals with and without atopic eczema. Dermatitis on the scalp was negatively associated with polysensitization (OR 0·66) primarily for individuals without atopic eczema. The dermatitis did not seem to be more widespread in polysensitized compared with single/double-sensitized patients.
Conclusions  Special awareness in patients with hand dermatitis seems justified either to prevent development of multiple contact allergies or to document polysensitization as an aetiological factor.     

Expression of CD30 on T helper cells in the inflammatory infiltrate of acute atopic dermatitis but not of allergic contact dermatitis

Abstract  The CD30 molecule has been proposed as a marker for a subset of CD4⁺CD45RO⁺ (memory) T cells with potent B cell helper activity producing IL-5 and IFN-γ and as a specific marker for Th2 cells. Recently, an association has been demonstrated between elevated serum levels of soluble CD30, which is shed by CD30⁺ cells in vitro and in vivo, and atopic dermatitis but not respiratory atopic disorders or allergic contact dermatitis. We studied the expression of CD30 in the inflammatory infiltrate of atopic dermatitis compared with that of allergic contact dermatitis, with special regard to skin disease activity (acute vs subacute/ chronic). Biopsies were obtained from 16 patients suffering from atopic dermatitis (acute n = 6, subacute/ chronic n = 10), from 7 patients with acute allergic contact dermatitis and from 5 positive patch-test reactions. Paraffin-embedded as well as snap-frozen material was stained with anti-CD30 and anti-CD45RO mAbs according to standard procedures. Double-staining procedures for CD30CD3, CD30CD4, CD30CD45RO and CD30CD68 were also performed. Abundant CD45RO⁺ cells were detected both in atopic dermatitis and in allergic contact dermatitis lesions. We found scattered CD30⁺ cells in only one of six formalin-fixed paraffin-embedded acute atopic dermatitis biopsies, but in all of the respective snap-frozen specimens, possibly because CD30 expression on atopic dermatitis infiltrating cells is weak and sensitive to formalin fixation and paraffin embedding. CD30CD3 and CD30CD4 double staining identified CD30⁺ cells to be helper T lymphocytes. No significant CD30 expression (either in paraffin-embedded or in frozen material) could be found in subacute/chronic atopic dermatitis lesions or in any of the specimens of allergic contact dermatitis. The results suggest a specific regulatory function of CD30⁺ T cells in acute atopic dermatitis. With respect to the view that CD30 is a marker for Th2 cells, our observations confirm previous findings that Th2 cells predominate in the infiltrate particularly of acute atopic dermatitis. CD30 expression in acute atopic dermatitis but not in acute allergic contact dermatitis might be helpful in the histological differentiation of these disorders and in the further characterization of atopy patch testing. Received: 1 April 1998 / Received after revision: 28 May 1998 / Accepted: 3 July 1998     

Occupational contact dermatitis

The dermatologist should be aware of the many facets of occupational skin diseases, which can be caused by physical, chemical, and biological insults. The most common manifestation of occupational skin diseases is contact dermatitis (both irritant and allergic). Three factors point out the importance of occupational skin diseases as diseases that have a public health impact: 1) occupational skin diseases are common; 2) they often have a poor prognosis; and 3) they result in a noteworthy economic impact for society and for an individual. They are also diseases amenable to public health interventions. Specific industries and exposures may put a worker at risk of occupational contact dermatitis. The accuracy of the diagnosis of occupational contact dermatitis is related to the skill level, experience, and knowledge of the medical professional who makes the diagnosis and confirms the relationship with a workplace exposure. Prevention of occupational contact dermatitis is important, and a variety of prevention strategies are available.     

Inhibition of the IL-2-inducible tyrosine kinase (Itk) activity: a new concept for the therapy of inflammatory skin diseases

T-cell-mediated processes play an essential role in the pathogenesis of several inflammatory skin diseases such as atopic dermatitis, allergic contact dermatitis and psoriasis. The aim of this study was to investigate the role of the IL-2-inducible tyrosine kinase (Itk), an enzyme acting downstream of the T-cell receptor (TCR), in T-cell-dependent skin inflammation using three approaches. Itk knockout mice display significantly reduced inflammatory symptoms in mouse models of acute and subacute contact hypersensitivity (CHS) reactions. Systemic administration of a novel small molecule Itk inhibitor, Compound 44, created by chemical optimization of an initial high-throughput screening hit, inhibited Itk's activity with an IC50 in the nanomolar range. Compound 44 substantially reduced proinflammatory immune responses in vitro and in vivo after systemic administration in two acute CHS models. In addition, our data reveal that human Itk, comparable to its murine homologue, is expressed mainly in T cells and is increased in lesional skin from patients with atopic dermatitis and allergic contact dermatitis. Finally, silencing of Itk by RNA interference in primary human T cells efficiently blocks TCR-induced lymphokine secretion. In conclusion, Itk represents an interesting new target for the therapy of T-cell-mediated inflammatory skin diseases.     

Gelatinase expression at positive patch test reactions

Matrix metalloproteases (MMPs) are proteolytic enzymes involved in tissue remodelling and extracellular matrix (ECM) turnover. They are secreted in a latent form and activated at the cellular surface by a membrane type-1 MMP (MT1-MMP) and a tissue inhibitor of MMP-2 (TIMP-2) that is also responsible for striking a balance between the proteolytic enzymes and TIMP-2. In allergic contact dermatitis (ACD) patients, MMP-2 and MMP-9, two members of the MMPs family, were increased during the challenge phase, in involved but not uninvolved skin. In contrast, TIMP-2 was more evident in uninvolved than involved skin, while no differences were observed with regard to MT1-MMP staining. Comparing the serum of ACD patients with that of healthy subjects, these differences were not observed. These data suggest that MMP-2 and MMP-9 could play a role in the mechanisms inducing alterations of the epidermal architecture, and in the pathogenesis of the lesions.     

Occupational allergic contact dermatitis and patch test results of leather workers at two Indonesian tanneries

Background. Tannery workers are at considerable risk of developing occupational contact dermatitis. Occupational skin diseases in tannery workers in newly industrialized countries have been reported, but neither the prevalence of occupational allergic contact dermatitis nor the skin‐sensitizing agents were specifically examined in those studies. Objectives. To assess the prevalence of occupational allergic contact dermatitis in Indonesian tanneries, identify the causative allergens, and propose a tannery work series of patch test allergens. Patients/methods A cross‐sectional study in all workers at two Indonesian tanneries was performed to assess the prevalence of occupational contact dermatitis via a questionnaire‐based interview and skin examination. Workers with occupational contact dermatitis were patch tested to identify the causative allergens. Results. Occupational contact dermatitis was suspected in 77 (16%) of the 472 workers. Thirteen (3%) of these 472 workers were confirmed to have occupational allergic contact dermatitis. Potassium dichromate (9.2%), N,N‐diphenylguanidine (5.3%), benzidine (3.9%) and sodium metabisulfite (2.6%) were found to be the occupationally relevant sensitizers. Conclusions. The sensitization pattern showed some differences from the data in studies reported from other newly industrial countries. We compiled a ‘tannery work series' of allergens for patch testing. A number of these allergens may also be considered for patch testing in patients with (leather) shoe dermatitis.     

Nickel-elicited systemic contact dermatitis

20 patients with systemic contact dermatitis due to nickel are described. Of these patients, 15 were female and 5 were male. Their mean age was 24.8 years (16-51 years). All had experienced contact dermatitis in the umbilical area due to continual contact with metal belt-buckles or buttons. Then, with long- or short-term aggravation of such periumbilical dermatitis, commonly in summer, lesions spread to other sites such as the side of the neck, the flexures of the extremities, etc. All patients showed a positive patch test to nickel sulphate (2.5% in petrolatum) and the dimethylglyoxime test demonstrated the presence of free nickel on metal buttons or belt-buckles. Punch biopsies performed in 7 patients showed subacute dermatitis. After avoidance of continual exposure to objects containing nickel and foods rich in nickel, as well as treatment with oral antihistamines and topical corticosteroids, all patients improved or cleared. It has been reported that nickel can cause systemic contact dermatitis by some internal systemic route, such as oral intake, transfusion, inhalation, implantation of metal medical devices, etc. In our patients, we found that continual local skin contact could also elicit systemic contact dermatitis.     

CONTINUING MEDICAL EDUCATION REVIEW Occupational skin disease in hairdressers

Hairdressers belong to an occupational group that is commonly affected by occupational skin disease, specifically contact dermatitis, which may be allergic or irritant and, less commonly, contact urticaria. Occupational contact dermatitis predominantly affects apprentices, and atopy is a recognized risk factor associated with a poor prognosis. Repetitive wet work leading to irritant contact dermatitis, followed by exposure to allergens and the development of allergic contact dermatitis, are the main factors contributing to occupational contact dermatitis. Once developed, it is often difficult to manage and is a cause of significant morbidity. Early education, training and prevention is the best approach to the management of this disorder that is endemic among hairdressers.     

Persistent post-occupational dermatitis

Wall and Gebauer (Contact Dermatitis 1991: 24: 241-243) first described persistent post-occupational dermatitis (PPOD) as ongoing dermatitis for which there is no obvious present cause, precipitated by prior occupational contact dermatitis (OCD). We propose that individuals exhibiting PPOD lose the capacity for resolution of their condition upon removal from exposure to causative agents and subsequently develop persistent dermatitis, which can be continual or intermittent. Accordingly, we suggest modification of criterion 6 of the OCD criteria developed by Mathias (J Am Acad Dermatol 1989: 20: 842-848): 'Removal from exposure initially leads to improvement of dermatitis, however, over time there may be incomplete or no improvement, despite removal from exposures at work'. To satisfy the definition of PPOD, individuals must meet at least 4 of the 7 criteria, including the altered criterion 6. We present 6 cases of PPOD exemplifying these scenarios, which met the altered Mathias criteria. In some cases, subsequent failure to recognize the initial work relatedness of their skin conditions resulted in the termination of workers' compensation benefits. This situation is particularly relevant in the Australian context. The diagnosis of PPOD needs to be considered in all individuals with work-initiated dermatitis who present with ongoing endogenous-like eczema.     

Low allergenicity of clonidine impedes studies of sensitization mechanisms in guinea pig models

During clinical trials, a clonidine transdermal device has been found to induce clonidine-specific allergic contact dermatitis in up to 25% of patients during a treatment period of 1 year. Using 3 different guinea pig strains, development was attempted of an experimental guinea pig model that would allow for in-depth studies into the mechanism of sensitization, and a possible role of transdermal device components. Transient low-level clonidine allergy could be obtained only in a minority of animals, with severe sensitization procedures departing from epicutaneous applications, combined with intradermal (adjuvant) FCA injections. Sensitization was not potentiated by additional booster procedures, including cyclophosphamide pretreatment, nor any of the putative cofactors (UV-treatments, C. parvum or acetaldehyde involvement) studied. These results suggest that the persistent skin contacts in man, with transdermal devices for sustained drug delivery, generate unique conditions favouring the development of allergic contact dermatitis, which are difficult to mimic in experimental animal models. Thus, clinical allergy may develop even to extremely weak sensitizing drugs that can be safely used orally, and escape most currently available predictive contact allergy animal models. Clinical studies remain unavoidable for studying factors that may reduce sensitization rates to more acceptable levels.