Allergic contact dermatitis caused by topical herbal remedies: importance of patch testing with the patients' own products.

BACKGROUND: Natural ingredients have variable compositions, so their allergenic potencies may differ. OBJECTIVES: To retrospectively analyse subjects reacting to herbal remedies over the past 27 years, with the aim of (i) evaluating demographic characteristics and lesion locations, (ii) describing the frequencies of positive patch test reactions, (iii) identifing sensitization sources, and (iv) studying concomitant sensitivity. PATIENTS AND METHODS: In total, 15980 patients were patch tested between 1990 and 2016 with the European baseline series and/or other series, product(s) used, and, whenever possible, the respective ingredients. RESULTS: Altogether, 8942 (56%) of 15 980 patients presented with at least one positive reaction. Reactions to topical herbal medicines, most often applied to treat an eczematous condition, leg ulcers, or other wounds, were seen in 125 (0.8%), that is, 1.4% of the contact-allergic subjects. Hands, legs and feet were the most frequently affected body sites. Twenty-one botanical allergens were identified, the commonest being Myroxylon pereirae (balsam of Peru), Compositae plants, and tincture of benzoin. Many patients presented with multiple positive test reactions, and some did not react to the commercial allergens but only to the products used. CONCLUSIONS: Topical herbal remedies should not be applied on damaged skin, as multiple sensitization may develop. Moreover, patch testing with the culprit products is important for the diagnosis.

Non-fragrance allergens in specific cosmetic products.

OBJECTIVES: Reports about the nature of the ingredients responsible for allergic contact dermatitis caused by specific cosmetic products are scarce. METHODS: Between January 2000 and December 2010, the specific cosmetic products having caused allergic contact dermatitis, as well as the individual allergenic cosmetic ingredients present in them, were recorded by use of a standardized form. RESULTS: Among 11 different categories of cosmetic product, skin care products, followed by hair care and body-cleansing products, were most often involved. The presence of the allergenic ingredient(s) in a specific cosmetic product was confirmed according to the ingredient label in 959 of 1448 records. Six hundred and twenty-one of 959 concerned non-fragrance components, preservatives being responsible for 58% of them. Reactions to formaldehyde and formaldehyde-releasers were most often correlated with body-cleansing products, particularly 2-bromo-2-nitropropane-1,3-diol and skin care products. They were followed by the methylchloroisothiazolinone/methylisothiazolinone mixture, most frequently found as allergens in hair care and intimate hygiene products, and facial cleansers (in the last category together with diazolidinyl urea). Octocrylene was by far the most frequent (photo)allergen in sun care products. CONCLUSIONS: This study provides information on the presence and frequency of allergens in specific causal cosmetic products.

Is a low content in atranol/chloroatranol safe in oak moss-sensitized individuals?

BACKGROUND: Chloroatranol and atranol are degradation products of chloroatranorin and atranorin, respectively, and have been identified as important contact allergens in oak moss absolute (Evernia prunastri). OBJECTIVES: To investigate whether chemically modified extracts of oak moss produce positive patch test reactions in previously sensitized subjects. METHODS: A sample of oak moss was treated by a polymer-based method to reduce the content of the two main allergens, namely atranol and chloroatranol, from 3.4% to less than 75 p.p.m. and from 1.8% to less than 25 p.p.m., respectively. Fourteen subjects with positive reactions to oak moss from Trolab and/or Chemotechnique were patch tested to this sample, diluted 1% in petrolatum. RESULTS: The chemically modified sample reacted negatively in six but gave still positive reactions in eight subjects, with the same intensity as the commercially available oak moss patch test materials. CONCLUSIONS: Polymer-based treatment of oak moss extract reduces the allergenic elicitation potential in previously sensitized individuals only to a minor extent. The residual concentrations of atranol and chloroatranol being less than 75 p.p.m. and 25 p.p.m., respectively, are unsafe for the consumer.

Contact allergy to oak moss: search for sensitizing molecules using combined bioassay-guided chemical fractionation, GC-MS, and structure-activity relationship analysis.

In addition to pure synthetic fragrance materials several natural extracts are still in use in the perfume industry. Among them oak moss absolute, prepared from the lichen Evernia prunastri (L.) Arch., is considered a major contact sensitizer and is therefore included in the fragrance mix used for diagnosing perfume allergy. The process of preparing oak moss absolute has changed during recent years and, even though several potential sensitizers have been identified from former benzene extracts, its present constituents and their allergenic status are not clear. In the study reported here, we applied a method developed for the identification of contact allergens present in natural complex mixtures to oak moss absolute. The method is based on the combination of bioassay-guided chemical fractionation, gas chromatography-mass spectrometry analysis and structure-activity relationship studies. Our first results showed that atranol and chloroatranol, formed by transesterification and decarboxylation of the lichen depsides, atranorin and chloroatranorin, during the preparation of oak moss absolute, are strong elicitants in most patients sensitized to oak moss. Methyl-beta-orcinol carboxylate, a depside degradation product and the most important monoaryl derivative of oak moss from an olfactory standpoint, was also found to elicit a reaction in most patients.