The proportion of contact sensitization to environmental allergens in the 34 adult atopic patients was remarkable (14 of 34, 41%). Out of the verified contact allergens, nickel, fragrance mix, thiomersal and lanalcolum proved to be relevant. House dust mite and cat epithel proved to be the most common relevant aeroallergens. D. pteronyssinus and D. farinae sensibilization was high, particularly in patients with severe skin symptoms on the face, eyelids and hands. Pollens should be considered in patients with seasonal relapse of AD. Sensitization to animal epithel was usually indicated by the flare-up of skin symptoms upon contact with animals. The relevance of the eliciting effects of sensitization could easily be supported in most cases by the medical history and the distribution of skin symptoms. In some adult AD patients with long-lasting AD, the relevance of triggering factors is hard to determine.

Recently, a transglutaminase 3 knockout (TGM3/KO) mouse was generated that showed impaired hair development, but no gross defects in the epidermal barrier, although increased fragility of isolated corneocytes was demonstrated. Here we investigated the functionality of skin barrier in vivo by percutaneous sensitization to FITC in TGM3/KO (n=64) and C57BL/6 wild-type (WT) mice (n=36). Cutaneous inflammation was evaluated by mouse ear swelling test (MEST), histology, serum IgE levels, and by flow cytometry from draining lymph nodes. Inflammation-induced significant MEST difference (P<0.0001) was detected between KO and WT mice and was supported also by histopathology. A significant increase of CD4+ CD25+-activated T cells (P<0.01) and elevated serum IgE levels (P<0.05) in KO mice indicated more the development of FITC sensitization than an irritative reaction. Propionibacter acnes-induced intracutaneous inflammation showed no difference (P=0.2254) between the reactivity of WT and KO immune system. As in vivo tracer, FITC penetration from skin surface followed by two-photon microscopy demonstrated a more invasive percutaneous penetration in KO mice. The clinically uninvolved skin in TGM3/KO mice showed impaired barrier function and higher susceptibility to FITC sensitization indicating that TGM3 has a significant contribution to the functionally intact cutaneous barrier.

The authors followed the frequency of fragrance contact sensitization in Hungary in a multicentre study in the years 1998 and 1999. A total of 3,604 patients were tested with fragrance mix (FM), and positive reactions were observed in 294 (8.2%). In 160 FM hypersensitive patients, the study was continued with patch testing of the mix constituents (cinnamic alcohol, cinnamic aldehyde, eugenol, amyl cinnamic aldehyde, hydroxycitronellal, geraniol, isoeugenol, oak moss absolute). Of the patients tested, 70.6% produced positive reactions to the constituents. FM contact sensitization was mainly observed in female patients (74.4%). The incidence of contact urticaria in FM hypersensitive patients was 6.1%. Simultaneous patch test trials of other environmental contact allergens, in both early and late evaluations, mainly confirmed hypersensitivity reactions to balsams. Female dominance of hypersensitivity reactions observed during testing the individual components of the mix was striking (82.4%). In positive skin reactions, cinnamic alcohol, isoeugenol and oak moss provoked skin symptoms most frequently. We also tested the 104 patients who produced negative reactions to FM with the constituent individual allergens, with 11.9% positive incidence. The clinical symptoms of the patients were above all manifest in the form of contact eczema, located on the hands, face, eyelids and axillae. With this study, the authors, members of the Hungarian Contact Dermatitis Research Group, call attention to one of the most frequent allergens in the environment.

EditorThere are only few data concerning the frequency of contact hypersensitivity (CH) in rosacea, 1-5 although it in fact can play an important role in the therapy or in the daily life of the patients.The aim of this study was to map the ratio of CH in 82 unselected rosacea patients (68 women, 14 men, over all 18 years, mean age: 54.4) tested in the Department of Dermatology, Venerology and Dermato-oncology of the Semmelweis University between January 2004 and December 2009.The patch tests were performed with Brial GmbH D-Greven series, and the reactions were evaluated (with 48 h occlusion) at 48, 72 and 96 h and on the 7th day. The patients did not take any antihistamine or immunosuppressive agents, and used only indifferent topical treatment 1 week before the tests and at the time of testing. Pregnancy, breast feeding, acute skin symptoms and UV radiation within 6 weeks before testing were drop-out criteria.CH was detected in 29 cases (35.4%). Most common allergens were nickel, balsam of Peru and fragrance mix I (Table 1). Among the relevant allergens, balsam of Peru (5 ⁄ 5), fragrance mix I (4 ⁄ 4), lanalcolum and PPD (3 ⁄ 3) were the most common. Relevant CH can rather be related to cosmetics (46.1%) and washing agents (38.4%). 38.8% of women face creams and make-ups and 20% lotions and gels were in connection with the CH. 27.8% showed CH as a component of therapeutic medical creams. At the time of testing, 80.5% of the patients were over 41 years. In 24 patients, the clinical symptoms had been present for 1-2 years, and in six cases, it was present for over 10 years. Two women had atopic dermatitis. The rosacea symptoms did not show correlation with the occupation of the patients.There is only few data about the ratio of CH in rosacea. [2][3][4][5] In this study, the ratio of CH to nickel (7.3%) meets previous data (3.4-15.5%), to that of balsam of Peru (6.1%) is lower than previous data (6.9-10.4%),and to that of fragrance mix I (4.9%) is lower than previous results (5.2-10.3%). [2][3][4][5] Rosacea patients are very susceptible to adverse reactions caused by external formulations, and so the choice of local treatment and cosmetics is difficult. The presence of CH must be kept in mind. According to our results, relevant CH associate mostly with cosmetics in rosacea patients.

Six patients with chronic urticaria are described in whom immediate type hypersensitivity to balsam of Peru was proven by patch test.