Contact dermatitis allergens producing

Whether or not chlorothalonil is a true dermal sensitizer in humans or strictly a skin irritant remains controversial. Some investigators suggest that repeated exposure results in an enhanced irritant response, whereas others suggest that it is a potent contact allergen. It is noted that relatively few cases of allergy to chlorothalonil have been reported despite widespread use for over 20 years. Furthermore, at a plant that produces the chemical cases of work-related contact dermatitis have not been reported for years after adoption of good hygienic practices. ... 

PBMC-derived DC serve as a surrogate marker for Langerhans cells (LC) and the chemical allergen-induced changes in cell surface markers of DC produce a similar pattern to those that occur in LC which are the antigen-presenting cell in the skin that plays a key role in the development of allergic contact dermatitis (Ozawa et al. 1996). 

TABLE 94—1. Common Allergens Producing Contact Dermatitis Among People in the United States. 

In a retrospective analysis of North American patients with suspected allergic contact dermatitis, balsam-of-Peru tree was the second most common allergen, with 11.6% of people tested producing positive reactions (Zug et al. 2009). Similarly, a retrospective study of patch test data from Denmark between 1985 and 2007 indicated that of the 16,173 patients tested, approximately 4% tested positively to balsam-of-Peru tree (Thyssen et al. 2008). 

Except for contact dermatitis, the route of administration appears to be of little importance in determining the type of hypersensitivity and clinical symptoms produced. Application of allergenic drugs to the skin is usually associated with a high incidence of sensitization (favorable conditions for the formation of conjugates ), whereas the oral route appears to be less likely to foster sensitization. Allergic reactions occur in about 2.5% of patients given penicillin G parenterally, in 5%... 

Epi-derm has received four reports of allergic contact dermatitis from phenol-formaldehyde resins and brake pad mixes (N. Cherry, personal communication). The medical literature has very few reports of dermatitis in the brake-lining industry. Phenol-formaldehyde resin is the main potential allergen in the occupational environment. Cashew-nut shell oil is well recognised as an allergen, but the materials used in brake linings rarely appear to sensitise. (Adams 1990). The species Anacardium occidentale produces cashew nuts. It is in the same family as poison ivy, oak and sumac found in North America and elsewhere. Cross-... 

Paraphenylenediamine (PPD) is a colorless compound oxidized by hydrogen peroxide in the presence of ammonia. It is then polymerized by a coupling agent to produce a color. Although a well-known allergen in hair dyes, PPD can be found as a cause of contact dermatitis in chin stains or in milk testers. It is also a marker for group sensitivity to para amino compounds such as benzocaine, para-aminobenzoic acid, azo-dyes and some sulphonamides. 

These compounds may act as allergens that produce dermatitis in contact with skin. Not much information is available regarding their toxicities to humans, although animal studies suggest several toxic effects, including hemolytic anemia. 

Proxymetacaine (proparacaine) in eye drops has been a contact allergen in one patient (Bandmann et al. 1974), and produced a scaling, fissuring dermatitis of the fingertips in an opthalmologist (March and Greenwood 1968) cross-sensitization with other local anesthetics did not occur. 

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