Formaldehyde-negative allergic contact dermatitis from melamine-formaldehyde resin.

Melamine-formaldehyde resin (MFR) is used as a textile finish, in tableware, in surface coatings, and in glues in the furniture and wood industry. MFR is considered to be an infrequent sensitizer. Contact allergy to MFR is often combined with formaldehyde allergy. Patients allergic to textile finish often react to MFR, although other finishes are nowadays more commonly used. Besides allergy to textile finish, allergic contact dermatitis from MFR has been described in workers in composite production and in an orthopaedic plaster technician. To our knowledge, there are no previous reports of contact allergy in the plywood industry from MFR. We describe 3 cases of occupational allergic contact dermatitis from MFR without contact allergy to formaldehyde, 1 in the plywood industry, 1 in the production of melamine-laminated chipboard and 1 in laboratory work.

Occupational contact urticaria from diglycidyl ether of bisphenol A epoxy resin.

BACKGROUND: Epoxy resin (ER) is a common cause of occupational allergic contact dermatitis (ACD), but contact urticaria from ER is very rare. METHODS AND RESULTS: A plastic-product worker first developed ACD from diglycidyl ether of bisphenol A (DGEBA) epoxy resin, and subsequent exposure resulted half a year later in contact urticaria: first with edema of the lips and eyelids, and later an urticarial reaction on the upper chest, with strong swelling of the eyelids and tightness of the throat. The diagnosis was based on a positive skin prick test to his "own" ER compound, a positive prick test reaction to DGEBA, and a positive skin provocation test with the ER compound and DGEBA. The contact urticaria test reaction was strongly aggravated when the allergen was wiped off with an alcohol solution, apparently because the solution enhanced the penetration of the allergen. CONCLUSIONS: Our case is of interest, first, because contact urticaria from ER is very rare, and second, because this is the second report in which a strongly intensified contact urticaria reaction was provoked by an alcohol solution. We suggest that if the contact urticaria provocation test with low-molecular-weight chemicals is negative, a contact urticaria provocation test with alcohol (CUPTA) should be performed.

Phthalic anhydride allergy: development and characterization of optimized hapten-carrier conjugates for improved diagnosis.

BACKGROUND: At present the diagnosis of IgE-mediated hypersensitivity to phthalic anhydride (PA) is based on conjugates that are not characterized or standardized. The aim of this study was to develop optimized and molecularly characterized PA conjugates that can be used to improve the diagnosis of PA-allergy. METHODS: The PA conjugates were synthesized and the number of haptens bound on a carrier protein was estimated by matrix-assisted laser desorption/ionization time of light (MALDI-TOF) mass spectrometry. The ability of conjugates to bind IgE and IgG antibodies was measured by enzyme-linked immunosorbent assay (ELISA). Reactivity of the conjugates in vivo was evaluated by skin prick testing. RESULTS: The most active IgE-binding conjugates had a PA : HSA molar ratio of 80 : 1. In the optimal conjugates the average numbers of PA haptens per carrier molecule of human serum albumin (HSA) were 14-16. In ELISA, all 13 patients and none of the 20 controls had IgE antibodies to optimized PA conjugate. The sensitivity and specificity of the ELISA was comparable to commercial CAP RAST. PA conjugates elicited positive test results in skin prick testing showing that conjugates are immunologically active also in vivo. CONCLUSIONS: These results indicate that optimized and molecularly characterized PA-HSA conjugates can be used both in vitro and in vivo assays to improve the diagnosis of PA allergy.

Occupational allergic contact urticaria to yucca (Yucca aloifolia), weeping fig (Ficus benjamina), and spathe flower (Spathiphyllum wallisii).

BACKGROUND: Occupational contact urticaria (CU) from plants is often reported, but it is less often attributed to decorative houseplants. We present an atopic gardener and caretaker of plants who developed CU when occupationally exposed to weeping fig, spathe flower, and yucca. METHODS: Sensitization was evaluated by skin prick tests (SPT) and analyses for IgE antibodies. RESULTS: SPT were positive to all three plants, and IgE antibodies were found to weeping fig and spathe flower. SPT were also performed with several decorative houseplants in more than 600 patients. Positive SPT was found to weeping fig (12%), African milk tree (8.3%), yucca (5.8%), Chinese rose (4.7%), massangana (4.6%), bird's nest fern (3.2%), and spathe flower (3.2%). CONCLUSION: Our study indicates that SPT and tests for IgE antibody are useful in detecting occupational CU caused by houseplants.

A multicenter study of patch test reactions with dental screening series.

BACKGROUND: Dental products contain many allergens, and may cause problems both for patients undergoing dental treatment and for dental personnel because of occupational exposure. Individual patch test clinics may not study sufficient numbers of patients to collect reliable data on uncommon allergens. OBJECTIVE: To collect information on dental allergens based on a multicenter study. MATERIALS AND METHODS: The Finnish Contact Dermatitis Group tested more than 4,000 patients (for most allergens, 2,300 to 2,600 patients) with dental screening series. Conventional patch testing was performed. The total number and percentage of irritant (scored as irritant [IR] or doubtful [?]) and allergic (scored as +, ++, or +++) patch test reactions, respectively, were calculated, as well as the highest and lowest percentage of allergic patch test reactions recorded by the different patch test clinics. A reaction index (RI) was calculated, giving information on the irritancy of the patch test substances. RESULTS: The most frequent allergic patch test reactions were caused by nickel (14.6%), ammoniated mercury (13%), mercury (10.3%), gold (7.7%), benzoic acid (4.3%), palladium (4.2%) and cobalt (4.1%). 2-hydroxyethyl methacrylate (2.8%) provoked most of the reactions caused by (meth)acrylates. Menthol, peppermint oil, ammonium tetrachloroplatinate, and amalgam alloying metals provoked no (neither allergic nor irritant) patch test reactions. CONCLUSION: Patch testing with allergens in the dental screening series, including (meth)acrylates and mercury, needs to be performed to detect contact allergy to dental products.

Occupational allergic contact dermatitis from alkylammonium amidobenzoate.

Quaternary ammonium compounds are water-soluble antimicrobials which are widely used in disinfectants, sterilizers, skin cleansers and antiseptic creams. One quaternary ammonium compound, alkylammonium amidobenzoate (Osmaron B) has for decades been used in udder ointments. Here we present a ship technician with occupationally induced sensitization to alkylammonium amidobenzoate. The diagnosis was reached only when it emerged, after careful questioning, that the patient was exposed to a substance peculiar to his workplace but not to his occupation and was then patch tested for it. It turned out that an udder ointment had been used at the patient's workplace as a hand ointment. Patch testing was positive to the patient's hand ointment, and Osmaron B at 0.1-0.01% in petrolatum. Other sensitizing quaternary ammonium compounds, namely benzalkonium chloride, benzethonium chloride, benzoxonium chloride, N-benzyl-N,N-dihydroxyethyl-N-cocosalkyl-ammonium chloride, cetalkonium chloride, cetylpyridinium chloride, cetrimonium bromide, chloroallylhexaminium chloride, dequalinium chloride, domiphen bromide, methylbenzethonium chloride and 2,3-epoxypropyl trimethyl ammonium chloride are reviewed briefly. The importance of patch testing to all materials in use by the patient is emphasized. It is also important to select non-allergenic hand creams for use at work places.

Asthma from diisocyanates is not mediated through a Type IV, patch-test-positive mechanism.

The mechanism of occupational asthma from diisocyanates (DI)(1-10)(Fig. 1) is not fully known; only about 10%-30% of such patients have specific IgE antibodies to DI (3, 11, 12). A T-cell mediated response has been considered to be involved in DI asthma (13) and we therefore wondered whether patch testing might be of any help in its diagnosis.

Occupational allergic contact dermatitis caused by wood dusts.

Exposure to wood dusts may cause various skin and mucosal symptoms. Allergic dermatoses, caused by wood dusts, diagnosed at the Finnish Institute of Occupational Health during 1976-1999 are reported here. 16 had allergic contact dermatitis and, 2 had contact urticaria. 9 men (3 cabinet makers, 3 joiners, 1 carpenter, 1 knifemaker and 1 machinist) were mainly exposed to tropical hardwoods. 1 man had dermatitis caused by western red cedar. 5 patients, 3 men and 2 women, were exposed to Finnish pine or spruce dusts, and 1 man to aspen. 7 also had rhinitis, 4 asthma or dyspnoea and 3 conjunctivitis. On patch testing, 10 men reacted to 9 different wood dusts, including teak (5), palisander (3), jacaranda (2), mahogany (2), walnut (2) and obeche (1). Reactions to wood allergens, including lapachol (2), deoxylapachol (1), (R)-3,4-dimethoxydahlbergione (2), 2,6-dimethoxy-1,4-benzoquinone (1), mansonone A (2) and salicyl alcohol (1), were noted in 4 cases. All but 1 of 5 patients exposed to pine or spruce dusts reacted to the sawdusts, all 5 to colophonium, 3 to abietic acid, 2 to tall oil resin, 3 to wood tar mix and 4 to other wood gum resins. Of the 2 CU patients, 1 was prick and RAST positive to obeche, 1 reacted with urticarial dermatitis to punah wood dust on chamber exposure. Occupational allergic dermatoses are mainly caused by the dusts of hardwoods, mostly due to Type IV allergy, but may also be caused by softwood dusts. Patch tests can be done with wood dusts, but should be confirmed by patch testing with wood allergens if possible.

Patch test sensitization to Compositae mix, sesquiterpene-lactone mix, Compositae extracts, laurel leaf, Chlorophorin, Mansonone A, and dimethoxydalbergione.

BACKGROUND: Compositae mix and sesquiterpene-lactone (SL) mix are important patch test substances to show allergic contact dermatitis from various Compositae plants. OBJECTIVES: The aims of this study are to calculate the sensitization rates to Compositae mix and SL mix in an occupational dermatology clinic and to describe cases of active sensitization caused by patch testing with Compositae mix and SL mix. METHODS: Conventional patch testing was performed. SL mix (0.1%) and Compositae mix (6% in petrolatum) were tested in a modified European standard series and a plant allergen series. Testing with other appropriate patch test series was also performed. RESULTS: SL mix provoked 8 allergic patch test reactions (0.7%) in 1,076 patients, whereas Compositae mix was positive in 15 of 346 patients (4.2%). Three patients were actively sensitized to Compositae mix and 1 patient to SL mix. One patient was also sensitized to other plant allergens in a series of allergenic plant chemicals, namely to Mansonone A, an ortho-quinone; (R)-3,4-dimethoxydalbergione, a quinone; and Chlorophorin, a hydroxy stilbene. Allergic patch test reactions to laurel leaf were caused by cross-sensitization to SLs. CONCLUSION: Compositae mix seems to be a more important patch test substance than SL mix to detect allergic contact dermatitis to Compositae plants, but patch testing may sensitize. The concentration of the individual components of the Compositae mix should be adjusted so that the mix detects allergic patients but does not sensitize.