captax and Dermatitis--Contact

Prior to 1979, there had been no reports of contact urticaria to rubber products. Since that time, many cases have been reported. At New York University, the first case, secondary to cornstarch allergy, was seen in 1985. Since that time, we have seen an additional six cases, five of them in the last year. Of these six cases, three were attributable to H. brasiliensis and three to the accelerators. Although the use of latex products has increased dramatically within the past 9 years in response to the epidemic of human immunodeficiency virus infections, it is not clear whether increased exposure alone accounts for the sudden increase in the number of patients with contact urticaria. Four of the patients presented here are hospital personnel involved in surgical procedures, in which, for decades, latex gloves have been used. Furthermore, two of our seven patients are paraplegics, who, as a group, have long had frequent exposure to rubber products. Two possibilities seem most likely: either the diagnosis has been missed by physicians for decades, or in response to the worldwide demand for latex products, the manufacture of latex has become altered in such a fashion that more products from which the allergens (accelerators and H. brasiliensis) are easily leached are now reaching the marketplace.

Topics: Adult; Benzothiazoles; Clothing; Contraceptive Devices, Male; Dermatitis, Contact; Dermatitis, Occupational; Female; Hand Dermatoses; Humans; Male; Middle Aged; Patch Tests; Pruritus; Rubber; Thiazoles; Urticaria

Risk assessment of sensitizing chemicals requires, besides hazard identification, the assessment of potency. To examine the sensitizing capacity of low molecular weight chemicals, a murine local lymph node assay (LLNA) was used. The sensitizing capacity of known allergens was quantified by dose-response modeling. At a stimulatory index (SI) of 3, the corresponding estimated concentration was calculated (EC(3)), together with a confidence interval to take account of the quality of the particular data set. We tested ten allergens (ethyl-p-aminobenzoate (benzocaine), diethylamine (DEA), 2,4-dinitrochlorobenzene (DNCB), 2-mercaptobenzothiazole (MBT), 4-ethoxymethylene 2-phenyl oxazol-5-one (oxazolone), phthalic anhydride (PA), toluene diisocyanate (TDI), trimellitic anhydride (TMA), tetramethylthiuramdisulfide (TMTD) and zincdimethyldithiocarbamate (ZDMC)). Oxazolone showed the strongest sensitizing potency followed in this order by DNCB, TDI, TMA, PA, TMTD, ZDMC, MBT, benzocaine and DEA. The approach performed in this study is a way to accurately assess the potency of sensitizing chemicals and thus a possibility for classification.

Topics: Allergens; Animals; Benzocaine; Benzothiazoles; Dermatitis, Contact; Diethylamines; Dinitrochlorobenzene; Dose-Response Relationship, Immunologic; Female; Linear Models; Lymph Nodes; Lymphocyte Activation; Male; Mice; Mice, Inbred BALB C; Oxazolone; Phthalic Anhydrides; Regression Analysis; Scintillation Counting; Specific Pathogen-Free Organisms; Thiazoles; Thiram; Toluene 2,4-Diisocyanate; Ziram

The guinea pig maximization test and the Buehler occluded patch test are used widely to identify the sensitization potential of new chemicals. This information enables toxicologists and/or regulatory authorities to determine whether a chemical should be classified formally as a skin sensitizer. Both to improve and to harmonize these assessments internationally, the OECD has recommended recently that moderate rather than strong contact sensitizers are used as positive control substances. The purpose is to ensure an adequate level of sensitivity in sensitization assays performed at specific testing establishments. Results from two laboratories reported here show that the minimum acceptable standard laid down by the OECD can be achieved and indeed commonly exceeded by a substantial margin. Furthermore, results with these positive controls in a new method, the local lymph node assay, also appear to satisfy similar criteria, suggesting results from this assay, including negative data, should be acceptable for classification purposes. However, a review of the way in which results with new chemicals will be interpreted for regulatory purposes, in the context of positive control data, reveals that considerable inadequacies still exist. It is recommended that ultimately, sensitization data can only be interpreted meaningfully (i.e. to protect humans from sensitization hazards) by considering the potency of the contact allergen in the context of the sensitivity of the assay performed at the particular testing institution.

Topics: Acrolein; Animals; Benzocaine; Benzothiazoles; Dermatitis, Contact; Guinea Pigs; Lymph Nodes; Mice; Mice, Inbred CBA; Skin Tests; Thiazoles

Topics: Benzothiazoles; Dermatitis, Contact; Dermatitis, Occupational; Hand Dermatoses; Humans; Male; Middle Aged; Oils; Thiazoles

Topics: Adolescent; Benzothiazoles; Dermatitis, Contact; False Positive Reactions; Foot Dermatoses; Humans; Male; Patch Tests; Seasons; Shoes; Thiazoles

Although contact dermatitis from shoes is common, the causative allergen is frequently not known. Reliance cannot be placed on standard screening trays because such testing can be negative when testing to shoe materials is positive. Furthermore, the relevance of positive screening tests is almost never proven by extracting that allergen from the patient's shoes. We present a case of insole dermatitis to tennis shoes in which we directly isolated the causative allergens by step-by-step patch-test monitoring of active fractions. Chromatographic separation of the active fractions led to the isolation of 2 allergens, mercaptobenzothiazole (Captax) (MBT) and its dimer, dibenzothiazyl disulfide (Altax) (DBTD). Patch tests to DBTD were noticeably more potent than those to MBT. In what might be considered an obvious case of contact sensitivity to MBT, the actual allergen is DBTD. Using this method, unknown shoe allergens can be isolated, identified, and added to the shoe test tray of potential allergens.

Topics: Benzothiazoles; Chemical Fractionation; Child; Chromatography; Dermatitis, Contact; Humans; Male; Patch Tests; Rubber; Shoes; Thiazoles

Topics: Adult; Artificial Limbs; Benzothiazoles; Dermatitis, Contact; Humans; Male; Rubber; Thiazoles

Topics: Adult; Benzothiazoles; Dermatitis, Contact; Diagnosis, Differential; Humans; Male; Mycosis Fungoides; Skin Neoplasms; Thiazoles

Topics: Aged; Benzothiazoles; Dermatitis, Contact; Humans; Male; Patch Tests; Thiazoles; Urinary Catheterization

Topics: Benzothiazoles; Dermatitis, Contact; Foot Dermatoses; Humans; Laundering; Male; Middle Aged; Shoes; Thiazoles

Topics: Benzothiazoles; Chemical Phenomena; Chemistry; Dermatitis, Contact; Humans; Rubber; Thiazoles

Topics: Benzothiazoles; Dermatitis, Contact; Drug Combinations; Humans; Patch Tests; Sulfhydryl Compounds; Thiazoles

Topics: Benzothiazoles; Dermatitis, Contact; Dermatitis, Occupational; Female; Humans; Middle Aged; Photography; Thiazoles

Mixes for patch testing conserve space and time. History and current usage of mixes are reviewed with comments on stability, concentration, consistency, use of infrequent allergens, vehicles and ingredients of mixes. Phenomena of 'aging', 'maturity', 'balance' 'stability' and 'quenching' have been studied elsewhere for naturally occurring mixes such as aroma chemicals (fragrances and flavorings). Little is known about any such changes for mixes of chemicals made for patch test purposes. The correct concentration of mercaptobenzothiazole (MBT) for MBT mix is discussed.

Topics: Benzothiazoles; Dermatitis, Contact; Humans; Patch Tests; Skin Tests; Thiazoles

A maximization test (after Magnusson & Kligman 1970), a single injection adjuvant test (SIAT) and a modified Draize test procedure for assessing contact sensitization potential in guinea-pigs have been compared for their ability to detect 19 known human contact sensitizers. The results show that the modified Draize procedure is a good screening test particularly for strong sensitizers. The maximization procedure is a very stringent test of sensitization potential, able to detect some marginal sensitizers. The sensitivity of the SIAT procedure is sufficiently similar to that of the maximization test to act as an alternative for routine testing, particularly in view of its practical advantages over the maximization procedure.

Topics: Adjuvants, Immunologic; Animals; Benzothiazoles; Dermatitis, Contact; Ethylenediamines; Guinea Pigs; Humans; Hydroquinones; Hydroxybenzoates; Immunization; Injections, Intradermal; Nickel; Potassium Dichromate; Skin Tests; Thiazoles

Topics: Amputation Stumps; Benzothiazoles; Dermatitis, Contact; Humans; Prostheses and Implants; Resins, Synthetic; Shoes; Thiazoles