Shoe contact dermatitis

The incidence of contact allergy was studied in a series of 165 patients with eczematous dermatitis of the feet correlated clinically with shoe contact. Positive reactions to one or more substances were recorded in 108 patients (65.4%). Among the relevant sensitizers were chromium, paraphenylenediamine, paratertiary butylphenolformaldehyde resin and nickel, while the other allergens were benzocaine, neomycin, balsam of Peru, ethylenediamine and parabens. Allergic contact dermatitis of the feel can he prevented by recognition of the allergens responsible, control of hyperhidrosis and avoidance of topical allergens.     

Enhanced sensitization and elicitation responses caused by mixtures of common fragrance allergens

Background. Perfumes are complex mixtures composed of many fragrance ingredients, many of which are known to be only weak allergens when tested individually. It is therefore surprising that fragrance contact allergy is one of the most common forms of contact allergy. Objectives. To investigate whether mixing different fragrance allergens leads to increased sensitization potency, and to examine the difference in the challenge response to one chemical in mice sensitized either with the mixture of allergens or with only the relevant allergen. Methods. CBA mice were sensitized with three different concentrations of three fragrance allergens alone or as a mixture. The sensitization and elicitation responses were measured by ear thickness plus infiltration of B and T cells and T cell proliferation in the draining lymph nodes. Results. We found a dose‐dependent sensitization response for each of the allergens. An increased response was seen when the allergens were mixed. A stronger challenge response to cinnamal was seen in mice sensitized with the allergen mixture than in mice sensitized with cinnamal alone. Conclusions. Our findings suggest that mixtures of allergens increase the primary response that potentiates the generation of memory T cells in response to the specific allergen. Thus, allergen mixtures enhance both induction and elicitation of contact allergy.     

Optimization of an in vitro lymphocyte blastogenesis assay for predictive assessment of immunologic responsiveness to contact sensitizers

Current methods for the predictive and diagnostic assessment of contact sensitization rely on the visual scoring of skin reactions. Predictive animal tests, generally using guinea pigs, require a relatively large number of animals to produce a sufficient database for interpreting skin reaction scores. In vitro assays have the potential of being more quantitative than skin testing and, if so, would require fewer animals. However, although in vitro assays are commonly used to study the cellular immune response to strong contact sensitizers, there has been little effort to validate them for predictive assessment purposes. We have optimized an in vitro lymphocyte blastogenesis assay for detecting the response of mouse lymphocytes to strong contact sensitizers with the eventual objective of applying this assay to moderate and weak sensitizers as well. Lymph node lymphocytes from mice sensitized to the strong contact allergens, dinitrochlorobenzene (DNCB), dinitrofluorobenzene (DNFB), or trinitrochlorobenzene (TNCB), responded [greater than or equal to 12,000 counts per minute (CPM) above background] when cultured with water soluble chemical analogues, di- or trinitrobenzene sulfonic acid (DNBS or TNBS). However, the strong sensitizer, oxazolone (OXAZ), has no water soluble analogue and lymphocytes from mice sensitized to OXAZ responded poorly in vitro (less than 2000 CPM) to an ethanol-solubilized OXAZ preparation in spite of very strong in vivo sensitization (ear swelling assay). To increase the assay sensitivity, for OXAZ, we modified the antigen presentation conditions by using 1) solubilized antigen-modified adherent spleen cells, 2) dendritic cells from the draining lymph nodes of antigen painted mice, and 3) antigen-modified Langerhans cell-enriched cultured epidermal cells (EC). These approaches increased OXAZ-directed responses to greater than 7000, greater than 20,000, and greater than 100,000 CPM, respectively, under culture conditions optimized for cell density, responder: stimulator cell ratio, culture duration, and responder cell type. Our results represent a first attempt to directly modify cultured epidermal cells with OXAZ and use these cells to stimulate OXAZ-directed blastogenesis in microtiter plate cultures. This optimized assay is now under evaluation for predictive assessment of contact sensitizers relevant to occupational and consumer exposures.     

Contact sensitivity to topical antimicrobials

A predictive study comparing the sensitizing potentials of some topical antimicrobials, using a modified Beuhler's technique, showed that over-the-counter (OTC) antimicrobials were more sensitizing than prescribed topical antibiotics. Among OTC antimicrobials, proflavine was the most potent sensitizer (4/10 guinea pigs); parachlorometaxylenol, benzalkonium chloride and propamidine isethionate moderate sensitizers (2/10 guinea pigs); iodine a weak sensitizer (1/10 guinea pigs); and chlorhexidine and cetrimide very weak sensitizers (0/10 guinea pigs). Among prescribed topical antibiotics, neomycin was a moderate sensitizer (2/10 guinea pigs); gentamycin and chloramphenicol weak sensitizers (1/10 guinea pigs); kanamycin, clioquinol, polymyxin B, bacitracin, tetracycline, sodium fusidate and fusidic acid very weak sensitizers (0/10 guinea pigs). There was good correlation between sensitizing potentials in animal studies and clinical experience of contact allergy to these topical antimicrobials.     

A successful murine model for contact sensitization to a sesquiterpene-alpha-methylene-gamma-butyrolactone: sensitization to alantolactone in four strains of mice

Induction of allergic contact hypersensitivity to a sesquiterpene lactone, alantolactone, was studied in four strains of mice: C3H/He, DBA/2, Balb/b, and Balb/c. The last three were successfully sensitized. A significant dose/response was demonstrated in these species, as well as an experimental "overload effect" in Balb/c and Balb/b strains. Histologic studies confirmed the allergic nature of the reaction. From the overall results, alantolactone can be considered a moderate sensitizer in mouse as well as in guinea pig. This study shows that the murine model can be used for experimental contact sensitization with moderate allergens, without the use of Freund's adjuvant for induction.     

Facial Contact Dermatitis

In 107 cases of facial contact dermatitis, routine Finn chamber epicutaneous tests with TROLAB European Standard Allergens (ESAs) were performed. Sixty-one (57%) had positive reaction. The most frequent contact allergens were paraphenylenediamine dihydrochloride (16%), followed by fragrance mix (15%), and nickel sulfate (13%). The major sensitized contactants were rims of spectacles, hair dyes, cosmetic creams, and topical medications. Among the cases caused by cosmetic cream, the positive allergens were fragrance mix, formaldehyde, wood alcohols, and balsam of Peru. In ten season-incidence cases in which ESAs and cosmetic cream epicutaneous tests were negative, the chamber and scratch-chamber tests were performed using five kinds of pollen. The results show that all chamber tests were negative, but two cases with scratch-chamber tests were positive.     

Sensitization of mice to topically applied drugs: albuterol chlorpheniramine, clonidine and nadolol

Allergic contact dermatitis from drugs is a significant obstacle to the development of transdermal drug delivers systems. Protocols for the sensitization of mice to drugs are needed to test methods for the prevention of allergic contact dermatitis. CBA/J female mice were sensitized to the drugs albuterol, chlorpheniramine, clonidine and nadolol by topical application. Sensitization was achieved by application of drug at 5% (w/v) 10 shaven dorsal skin for 5 days in a hydroxyethylcellulose vehicle. Contact serialization was determined by measuring the car swelling response to application of l%. drug in vehicle. Control mice treated by application of vehicle alone did not exhibit an ear swelling response to drug. Supplementation of the mice with vitamin A boosted the ear swelling response, as did application of drug to dorsal versus abdominal skin. Although plasma amounts of retinol were higher in vitamin A supplemented versus control mice, the rate of drug (albuterol and nadolol) permeation was not significantly different between vitamin A supplemented and control mice. Permeability of dorsal skin for nadolol was twice that of ventral skin, which may explain the differences in sensitization at these sites. This sensitization protocol should be useful in the development of hypoallergenic transdermal drug delivery systems.     

Contact allergens in patients with leg ulcers

Background Contact dermatitis can complicate the treatment of leg ulcers and is an acquired phenomenon resulting from the use of topical medications.
Objective To show the incidence of contact dermatitis reactions to topical medications applied to leg ulcers and to evidence changing trends in such reactions through comparison of two case series about 20 years apart.
Subjects and methods We studied two groups of patients with leg ulcers that were patch tested with contact allergens in 1973–1974 and in 1994–1995.
Results One or more positive patch tests was present in 75% and 40% of the patients, respectively. A decrease in the incidence of positive reactions to neomycin, local anesthetics and parabens mix was seen in 1994–1995. The most important contact allergens in 1994–1995 were fragrance mix, colophony and the excipients wool alcohols and amerchol. Other relevant sensitizers were formaldehyde, neomycin and gentamycin.
Conclusion The changing trends in contact allergens over the last 20 years may be explained by changes in the components of topical agents used for treatment.     

Optimization of the mouse ear swelling test for in vivo and in vitro studies of weak contact sensitizers *

Murine models for the assessment of the contact sensitizing properties of chemicals rely on mouse ear swelling tests (Mest), which are not sensitive enough to detect weak sensitizers. The aim of the present study was to develop in mice an adjuvant-free Mest appropriate for in vivo detection of any type of sensitizer (weak to strong), and useful for in vitro assessment of contact sensitivity (CS). 3 haptens were tested: dinitrochlorobenzene (DNCB), para-phenylenediamine (pPD) and isoeugenol. We compared various protocols for induction of the CS reaction, differing by the site of induction, the number of applications and the concentrations of the 3 haptens. Comparison of the induction site for optimal CS reaction showed that, in Balb/c mice, the back was a better site of induction than the abdomen. Detection of the sensitizing properties of weak sensitizers (pPD, isoeugenol) was possible using an adjuvant-free protocol, provided that the induction phase comprised hapten applications on 3 consecutive days on the backs of animals. For DNCB, one application was sufficient to obtain optimal CS reaction. For all 3 haptens, a secondary response in vitro was obtained using semi-purified lymph node T cells from animals sensitized 5 days before with the optimized Mest. These results demonstrate that the Mest could be a useful experimental model for the study of all types of contact sensitizers.     

Epidemiology of contact dermatitis in Marseilles (author's transl)]

Five hundred subjects were patch-tested on the one hand with 25 allergens standard group and on the other hand with selected allergens depending on the occupation and history of each patient. They systematic standard series are responsible for 79 p. 100 of contact allergens. Among them the most frequent sensitizers observed include potassium dichromate, nickel sulfate, cobalt chloride, paraphenylenediamine, propylene-glycol, triethanolamine, balsam of Peru. The selected allergens stand for 21 p. 100 of our cases. These results are compared with those of other countries. The main sensitizers are involved in every case. However a few discrepancies are to be noted: turpentine and mercury do not occupy with us a foremost rank, whereas prophylene-glycol and triethanolamine which, according to our statistics, stand fourth and seventh, are not mentioned elsewhere. Differents factors can partly account for these variations: industrial products are submitted to local influence, as it occurs with turpentine for instance, environmental factors play an important part too and, above all, local industries. Nevertheless, this study brings into relief two facts:--the interesting use of systematic standard series, constantly updated, since they are responsible for 79 p. 100 of contact allergens;--the incidence of each patient's history and occupation on the choice of selected allergens, thanks to which we can put into relief less usual causes, though they should not been overlooked, since they stand for 21 p. 100 of the allergens so far listed.     

The frequency of contact sensitivity in North America 1972–74 North American Contact Dermatitis Group

Three thousand subjects in North America were patch-tested with 19 allergens. The most frequent sensitizers observed include nickel sulfate, caine mixture, potassium dichromate, balsam of Peru, thimerosal, ethylenediamine hydrochloride, paraphenylenediamine and thiram. The prevalence data compared with an earlier study indicates that the initial allergens reported warrant their continued inclusion in a routine patch test screening series in North America.     

A murine in vitro model of allergic contact dermatitis to sesquiterpene α-methylene-γ-butyrolactones

Summary The use of a lymphocyte transformation test (LTT) to provide evidence of allergic contact dermatitis was investigated. The haptens studied were alantolactone and isoalantolactone, two moderate allergens from Inula helenium L., a decorative and medicinal plant. Only alantolactone showed a significant response in vivo and in vitro in mice sensitized epicutaneously, without using Freund's complete adjuvant. Isoalantolactone did not show any sensitizing capacity in the murine model studied. The comparison of in vitro lymphocyte proliferation and in vivo allergenic capacity showed a good correlation and clearly demonstrates that, of the two sesquiterpene lactones, alantolactone is the better sensitizer.In memory of Prof. C. Benezra and Dr. R. Fraginals accidentally deceased     

Several different ion channel modulators abrogate contact hypersensitivity in mice.

A major obstacle in transdermal delivery of drugs is the development of adverse skin sensitization reactions. We tested the concept that ion channel modulators as a class of agents suppress contact hypersensitivity in a mouse model. Mice were sensitized to several contact sensitizing chemicals including dinitrochlorobenzene (DNCB) and a sensitizing drug, nadolol. We report our successful use of several ion channel modulators in suppressing contact hypersensitivity, including amiloride, ethacrynic acid (ECA), nifedipine and verapamil. For this purpose, Balb/c female mice were sensitized with DNCB, and abrogation of induction of contact hypersensitivity reaction (CHR) was examined by topical pretreatment of the target-sensitized skin with amiloride, nifedipine and pairwise combinations of these agents with ECA, a potassium ion channel blocker. Abrogation of induction of CHR was observed in all cases. In addition, suppression of contact hypersensitivity was observed in nadolol-sensitized mice pretreated with either verapamil or nifedipine. The results indicate that ion channel inhibitors are broadly effective inhibitors of allergic contact dermatitis and may be useful for facilitating the transdermal delivery of therapeutic drugs that have sensitization potential.     

Contact dermatitis from antioxidants

In a search for contact sensitivity to antioxidants we patch tested consecutive patients referred with eczematous dermatitis. Six cases of allergic contact sensitivity to nordihydroguairetic acid (NDGA) were observed. Three had been sensitized by one brand of cream containing 0.1% NDGA, in three patients the source of sensitization could not be traced. In four patients we found positive patch tests to butylated hydroxyanisole and/or to butylated hydroxytoluene. In two cases the positive patch tests were relevant, since both patients remained asymptomatic when antioxidants were avoided in food. They both had acute flares of vesicular eczema on the fingers after oral administration of small amounts. Gallate esters and Vitamin E (d,l-alpha-tocopherol) each gave one unexplained positive patch test. The present data suggest that further search for hidden sensitizers in topical medicaments and cosmetics is warranted. A declaration of all ingredients in industrial products should be placed on the label.     

The suitability of hexyl cinnamic aldehyde as a calibrant for the murine local lymph node assay

The murine local lymph node assay (LLNA) for the prospective identification of contact allergens assesses skin sensitization potential as a function of proliferative activity induced in lymph nodes draining the site of topical exposure to test chemical. This method has been endorsed recently as a stand alone test for the identification of contact allergens. We have now examined the suitability of hexyl cinnamic aldehyde (HCA), a recommended positive control for skin sensitization testing, as a calibrant for comparing the consistency of LLNA responses with time, and between laboratories, and thus for the routine assessment of assay reliability. Standard LLNAs were performed with CBA strain mice in 3 independent laboratories over a period of 8 years. Dose-response curves were used to derive mathematically the EC3 value (the estimated concentration of chemical necessary to cause a stimulation index (SI) of 3 compared with proliferation induced by concurrent vehicle controls). In each laboratory, 6 separate experiments were conducted using a single concentration of HCA (25%). Very similar stimulation indices were achieved, with mean values of 9.0, 6.5 and 6.6 recorded. A total of 10 dose-response experiments were performed independently in the 3 laboratories and these revealed that there was very little inter-laboratory, or temporal, variation in EC3 values. These data confirm that HCA responses in the LLNA are very stable and demonstrate that HCA provides a suitable calibrant for determining assay sensitivity and performance.     

Oral tests in contact allergy to para-amino compounds

A group of 34 inpatients with contact allergy to para-amino compounds (sulfanilamide, paraphenylenediamine, benzocaine) underwent a series of peroral tests using structurally related substances, sulphonvl ureas (carbutamide, tolbutamide and chlorpropamide), diaminodi-phenyl-sulfone. saccharin and salicyl azosulfapyridine. Sulphonyl ureas given orally can produce a widespread dermatitis in subjects with contact sensitivity to sulfanilamide. but not in those sensitized to paraphenylenediamine and benzocaine.     

Acute stress enhances contact dermatitis by promoting nuclear factor‐κB DNA‐binding activity and interleukin‐18 expression in mice

Psychological stress adversely affects the immune system, and aggravates various skin diseases, such as psoriasis, alopecia areata and atopic dermatitis. However, the precise underlying mechanisms remain to be elucidated. The goal of this study was to use a murine restraint stress model to determine the mechanisms by which psychological stress modulates immune response in contact dermatitis. In the present study, mice were sensitized and challenged on the skin with 2,4‐dinitrofluorobenzene. Acute restraint stress was administrated to healthy or sensitized mice before challenge, and nuclear factor (NF)‐κB DNA‐binding activation of nuclear protein and expression of interleukin (IL)‐18 mRNA in murine spleen lymphocytes was detected. Chemical sympathectomy was performed using the neurotoxin 6‐hydroxy‐dopamine to determine the effect of the sympathetic nervous system. The experiment showed that restraint stress induced a series of changes which include increasing of NF‐κB DNA‐binding activity and IL‐18 mRNA expression in spleen lymphocytes and enhancement of contact hypersensitivity response, and these changes may be mediated by the sympathetic nervous system. These findings provide new insights into the roles of the nervous system in the aggravation of skin diseases.     

面部接触性皮炎致病因素的调查

作者应用TROLAB欧洲标准抗原对107例面部接触性皮炎患者进行芬兰斑试器斑贴试验(Finn Chamber Epicutaneous Test)。结果61例(57.01%)出现阳性,其主要致敏原为对苯二胺(15.89%)、硫酸镍(13.08%)、芳香混合物(14.95%)。其主要致敏物分别为金属眼镜架、染发剂、化妆品和外用药。化妆品过敏的皮炎患者,欧洲标准抗原阳性者为芳香混合物、甲醛、羊毛脂及秘鲁香油。欧抗及化妆品斑试阴性、呈季节性发病者10例又进行了五种花粉的斑试及划痕-斑试(Scratch-Chamber)试验。结果斑试全部阴性,但其中2例划痕-斑试阳性。     

The coumarin herniarin as a sensitizer in German chamomile [Chamomilla recutita (L.) Rauschert,Compositae]

Background: Although German chamomile (Chamomilla recutita) is considered a weak sensitizer, recent studies have shown several possible non‐sesquiterpene lactone allergens in tea (infusions) from the plant. Objective: The aim of this study was to report the results of patch testing with herniarin (7‐methoxycoumarin), which is one of the possible coumarin allergens in chamomile. Patients/materials/methods: Between 1991 and 2009, selected patients with known or suspected Compositae contact allergy were patch tested with herniarin 1% petrolatum. Results: Among 36 patients tested, there was one positive and three doubtful positive reactions to herniarin. All 4 patients had a relevant contact allergy to German chamomile, whereas the majority of the remaining 32 patients had chamomile allergy of unknown relevance. Conclusions: The clinical results suggest that herniarin indeed is one of the non‐sesquiterpene lactone sensitizers in German chamomile and that sensitization may occur through, for example, external use of chamomile tea or use of chamomile‐containing topical herbal remedies.     

Postelicitation model of allergic contact dermatitis for predicting the efficacy of topical drugs

Abstract:  To evaluate the anti-inflammatory efficacies of topical drugs, models of contact hypersensitivity (CHS) can be used, but the conventional murine models of CHS need revision in this respect. These models utilize sensitized mice to study suppression of sensitization or elicitation by test compounds. To mimick the events occurring in allergic contact dermatitis (ACD), a modification of the murine model of CHS is needed in a way that a chronic postelicitation phase of CHS is maintained for studies of anti-inflammatory effects of topical drugs, typically relevant for ACD therapy, not for ACD prevention. A method for the quantification of the suppression of ACD by a test compound is presented here. Two experimental drugs for topical use, imidazole-4-carboxylate and imidazole-4-acetate, were tested in parallel with the corticosteroid prednisolone. We found that prednisolone showed strong suppressive effects, while imidazole-4-carboxylate and imidazole-4-acetate showed mild suppressive effects during persistent ACD simulation. Multiple elicitations on the mouse ears led to scratching and the formation of abrasions and scabbings with, presumably, worsening of discomfort. Clear reduction of these side-phenomena was achieved by tailoring the topical amount of contact sensitizer, while the ability of the ACD model to test anti-inflammatory compounds, was not affected. By focussing on a prolonged postelicitation phase of CHS, a simulation of ACD has been established. We demonstrated that this model may provide an improved predictability for the clinical efficacies of (experimental) mild or strong anti-inflammatory drugs.