Contact allergy to topical corticosteroids occurs more frequently than previously supposed. Cross-allergic phenomena are common. On the basis of a review of the literature and our own patch test data on 15 patients, we conclude that positive patchtests to corticosteroids occur approximately six to seven times more frequently in well-defined groups of structurally-related substances than between corticosteroids of different groups. An analogous substitution pattern on the steroid D-ring or the carbon side chain (C20, C21) seems to have a significant influence on the association of positive patchtest results. This is not the case for other structural variables, such as the presence of a double bond in the steroid A-ring or fluoride substitutions on the B-ring. The effect of other factors such as concomitant sensitization and steroid metabolism in the skin on the development of a corticosteroid polyallergy are analysed, and the specificity and sensitivity of cross-allergy phenomena are evaluated. These are important in the selection of a topical steroid in the future treatment of a corticosteroid sensitive patient.

d-Limonene, obtained as a by-product from the citrus juice industry, was introduced on the market as a more environmentally friendly defatting and cleaning agent than the traditionally used organic solvents. Autoxidation of d-limonene readily occurs to give a variety of oxygenated monocyclic terpenes that are strong contact allergens. The aim of the present study was to investigate the prevalence of contact allergy to air exposed d-limonene among dermatitis patients. A fraction consisting of d-limonene hydroperoxides was also tested. Screening with oxidized d-limonene will detect cases of allergic contact dermatitis. Additional cases were detected when testing with the fraction of limonene hydroperoxides. The proportion of positive patch test reactions to oxidized d-limonene was comparable to that seen for several of the allergens within the standard series. An increased use of d-limonene containing allergenic oxidation products in industry where high concentrations are used, as well as in domestic exposure, might result in contact sensitization and dermatitis. Patients reacting to d-limonene often reacted to fragrance mix, balsam of Peru and colophony in the standard series.

The objective of this study was to determine the frequency of reactivity to a series of commonly used fragrances in dermatological patients. A total of 48 fragrances (FF) were chosen, based on the publication of Fenn in 1989 in which the top 25 constituents of 3 types (1. perfumes, 2. household products, 3. soaps) of 400 commercial products on the US market had been determined. In a pilot study on a total of 1069 patients in 11 centres, the appropriate test concentration and vehicle were examined. For most fragrances, 1% and 5% were chosen, and petrolatum proved to be the best vehicle in comparison to isopropyl myristate and diethyl phthalate. In the main study, a set of 5 to 10 fragrances at 2 concentrations was patch tested in each centre on a minimum of 100 consecutive patients seen in the patch test clinic. These patients were also patch tested to a standard series with the 8% fragrance mix (FM) and its 8 constituents. In patients with a positive reaction to any of the 48 FF, a careful history with regard to past or present reactions to perfumed products was taken. A total of 1323 patients were tested in 11 centres. The 8% FM was positive in 89 patients (8.3% of 1072 patients). Allergic reactions to the constituents were most frequent to oak moss (24), isoeugenol (20), eugenol (13), cinnamic aldehyde (10) and geraniol (8). Reactions read as allergic on day 3/4 were observed only 10X to 7 materials of the new series (Iso E Super (2), Lyral (3), Cyclacet (1), DMBCA (1), Vertofix (1), citronellol (1) and amyl salicylate (1)). The remaining 41 fragrances were negative. 28 irritant or doubtful reactions on day 3/4 were observed to a total of 19 FF materials (more than 1 reaction: 5% citronellol (2), 1% amyl salicylate (2), 1% isononyl acetate (3), 0.1% musk xylol (2), 1% citral (2), and 1% ionone beta (2)). Clinical relevance of positive reactions to any of the FF series was not proved in a single case. This included the 4 reactions in patients who were negative to the 8% FM. In conclusion, the top 25 fragrances commonly found in various products caused few reactions in dermatological patients and these few appeared to be clinically irrelevant, with the possible exception of Lyral. However, this data should be interpreted in the light of the relatively small number of patients tested (only 100 in most centres).

Protein contact dermatitis is a dermatosis which usually presents as a chronic eczema with episodic acute exacerbations a few minutes after contact with the offending allergen. Patch tests with the responsible allergen are usually negative, and the diagnosis can only be made by means of scratch or prick tests with the allergen. Sometimes, specific IgE antibodies can be detected in the blood. As there is considerable confusion about this entity, we have reviewed the cases reported in the literature.

The patch test results of 61 patients allergic to at least 1 corticosteroid molecule are presented. These contact allergies were detected by testing with several corticosteroids included in our standard patch test series between February 1988 and December 1990. Whenever possible, further investigations were conducted by means of a more complete corticosteroid series. We found corticosteroids to be the 7th most frequent allergen, positive results being obtained in 2.9% of all patients referred to our contact dermatitis unit. In this series, budesonide was the most common allergen and often gave simultaneous reactions with other corticosteroids.