American journal of contact dermatitis : official journal of the American Contact Dermatitis Society最新文献

A 35-year-old man presented with a 2-month history of intensely pruritic excoriated and crusted linear lesions on the dorsa of the left hand and left forearm (Fig 1). The patient had worked in construction for 2 years, and his job consisted mainly in covering the facades of buildings with cement. The patient was right-handed and used a black rubber glove as a protective measure only on his left hand (Fig 2). He reported that the lesions resolved partially during holidays and weekends and clearly flared in association with his work. There was no history of atopic dermatitis, drug use, or intolerance to metals, rubber, or fruits. On physical examination, linear excoriations with crusts were observed on the dorsa of the left hand, extending to the ventral and dorsal aspects of the forearm, involving the whole area that was in contact with the glove. Lichenified erythematous plaques and excoriations on the dorsal surface of the metacarpophalangeal joints and scaly lesions on the dorsal surfaces of the fingers were also present. On the palm, only discrete hyperkeratosis was seen. The right hand and forearm were free of lesions. He complained of intense pruritus when wearing the rubber glove and admitted to continuous scratching to relieve his discomfort, inducing the linear and excoriated lesions. Treatment with topical corticosteroids was initiated, with progressive resolution of the lesions.

The aims of the Research Institute for Fragrance Materials, Inc. (RIFM), an international nonprofit science-based organization established in 1966 by the fragrance industry, include the prevention of adverse cutaneous effects, systemic toxicity, and environmental consequences from fragrance ingredients. This paper gives an overview of the RIFM testing and research program, how priorities are established, and how RIFM's safety evaluation process works.

The diagnosis of allergic contact dermatitis of the feet is challenging because the constituents of shoes are not labeled. In addition, the materials and technologies used in the manufacturing of shoes are continuously evolving. Since the 1950s, rubber allergens have been the most common cause of shoe dermatitis. However, the causal allergens in rubber have changed. Instead of 2-mercaptobenzothiazole, dithiodimorpholine, an allergen that is not contained on standard patch-testing trays, now may be one of the more common rubber sensitizers in shoes. Other allergens not found on standard series that can account for shoe dermatitis include isophorone diisocyanate, dimethylaminoethyl ether, and mixed dialkyl thioureas. Therefore, physicians evaluating patients with allergic-appearing foot dermatitis need to test with allergens beyond those present on standard screening series.

Background: Eyelids can be affected by various types of dermatitis that are often difficult to diagnose.

Objective: The aim of the study was to establish some guidelines for a correct diagnosis.

Methods: A total of 447 patients treated at 12 research units for eczema or other inflammatory dermatitis located on the eyelids were invited to complete a questionnaire. When necessary, patch tests with haptens of the standard series from Gruppo Italiano di Ricerca sulle Dermatiti da Contatto e Ambientali della Società Italiana di Dermatologia e Venereologia (SIDEV-GIRDCA) were performed.

Results: Of the subjects studied, 50.2 % were diagnosed with allergic contact dermatitis (ACD); 20.9% were affected by irritant contact dermatitis (ICD), 13.5% by atopic dermatitis, 6.3% by seborrheic dermatitis, 6.5% by aspecific xerotic dermatitis, and 2.3% by psoriasis. Approximately 91% of all subjects reported an absence of familial atopy. A significant statistical association between diagnosis type and a personal history of atopy was evident (p <.000001, chi-square test). The results of gradual logistic regression models showed four-eyelid involvement as the main risk factor for ACD (odds ratio [OR] = 3.0; 95% CI, 1.1-8.1); with ICD, the main risk factor was the onset of symptoms at between 2 and 6 months (OR = 2.1; 95% CI, 1.1-4.0), whereas for atopic dermatitis, the main risk factors were the onset of symptoms later than 6 months and a personal history of atopy (OR = 4.9 and 3.6, respectively).

Conclusion: Results suggest that many characteristics of the patients examined can be used for the differential diagnosis of palpebral eczematous dermatitis.

Background: Nonterpenoid and diterpenoid phenanthrenequinones (PACs) have been found in the plant kingdom. Some of them occur in plants used in traditional Chinese medicine like Tan-Shen whereas others are constituents of orchids that are popular as ornamental plants.

Objective: Case reports and our own observations in orchid nurseries suggest that some or even all of these PACs possess a distinct sensitizing potency. Occasional exposure (particularly of botanists) to field-grown orchids, as well as occupational contact with sawdust of PAC-containing tropical timbers, caused allergic contact dermatitis. However, experimental studies in guinea pigs to determine the sensitizing capacity of PACs have not been performed so far.

Methods: Guinea pigs were sensitizied by a modified Freund's complete adjuvant method with four naturally occurring and 22 synthetic PACs in order to find out which and how many substituents at the carbons of the three rings of the PAC will influence the sensitizing power of the molecule. Subsequently, the lowest unoccupied molecular orbital (LUMO) coefficients were calculated to show whether a correlation exists between chemical reactivity and sensitizing capacity.

Results: Sensitizing capacity was found to be strong in two PACs, moderate in eight PACs, and weak in ten PACs. Five PACs were extremely weak in sensitizing capacity, and one PAC was completely negative. Two substituents on the left-hand carbons C-7 and C-8 of ring C were shown to be responsible for a strong sensitizing capacity. One methoxy group alone or three of them, especially when localized at C-5, decreased the sensitizing capacity to moderate. Substitution with a methoxy group at C-3 and/or at C-2 of the quinonoid ring itself (ring A) led to a weak sensitizing capacity. The ortho-quinones 1,2-PAC and 9,10-PAC were also weakly sensitizing. In fact, LUMO coefficient calculations corroborated a good correlation between chemical reactivity and sensitizing capacity.

Conclusion: Substitution with methoxy groups at C-7 and/or at C-8 of ring C of 1,4-phenanthrenequinone increases the LUMO coefficients at the 2,3 double bond of ring A and thus facilitates nucleophilic substitution of protein nitrogen or sulfur nucleophiles at this electron-deficient double bond. The four naturally occurring PACs that were investigated--cypripedin, denbinobin, annoquinone-A, and latinone--do not fulfill these criteria and are thus only weak sensitizers. However, as-yet-unstudied phenanthrenequinones occurring in plants or trees and having no substituents at C-2 or C-3 of the quinonoid ring must be considered potentially strong allergens.