Diluted Compositae mix versus sesquiterpene lactone mix as a screening agent for Compositae dermatitis: a multicentre study

The objective of this study was to compare diluted Compositae mix with sesquiterpene lactone mix as a marker for Compositae dermatitis. Patients undergoing diagnostic patch testing in 8 British Isles patch test centres were also patch tested to sesquiterpene lactone mix (0.1% pet.) and Compositae mix (3% pet. or 0.6% pet.). Of a total of 5574 patients tested, 71 (1.3%) reacted to Compositae mix, 57 (1.0%) reacted to sesquiterpene lactone mix, and 45 to both. Diluted Compositae mix remained a more sensitive screening marker for Compositae allergy. We recommend that patients are patch tested to both agents.     

Compositae mix is a more sensitive test for Compositae dermatitis than the sesquiterpene lactone mix

Over the past 2 decades, Compositae dermatitis has increasingly been recognized as a cause of exposure-pattern dermatitis. The introduction of the sesquiterpene lactone (SL) mix as a screening test has contributed to this improved recognition. However, there is growing evidence that the SL mix fails to detect a substantial number of genuine Compositae allergies. We therefore investigated whether another screening reagent (the Compositae mix) might be more sensitive in detecting cases of Compositae allergy than the SL mix. Over a 1-year period, we tested 656 consecutive unselected patch test patients to both SL mix and Compositae mix. 31 patients were found to have genuine Compositae allergies. Of these, 28 had reacted to the Compositae mix but only 13 had reacted to the SL mix. The Compositae mix failed to detect only 2 genuine Compositae allergies, whereas the SL mix missed 17 such allergies. On the other hand, the Compositae mix led to 9 irritant reactions, while there was only 1 irritant reaction with the SL mix. We conclude that Compositae dermatitis is still being underdiagnosed with the current screening method, and that the Compositae mix is significantly more sensitive in detecting Compositae allergy than the SL mix.     

Allergic contact dermatitis in food handlers, with patch tests positive to Compositae mix but negative to sesquiterpene lactone mix

Several studies have pointed out that the sesquiterpene lactone (SL) mix is a safe, though inadequate, screen for Compositae allergy. To test the usefulness of the sesquiterpene lactone parthenolide as a supplementary Compositae screening test to the mix, both were included in the standard series in 2 Danish dermatology departments. Among 2244 patients tested, 46 (2%) were positive to SL mix and 73–75% of these were positive to parthenolide. The results demonstrate that parthenolide is not suitable as a supplementary screening agent to SL mix, but may be a fairly good screen on its own if the mix is not available.     

Sesquiterpene lactone mix is not an adequate screen for Compositae allergy

70 patients suspected or known to have contact allergy to Compositae were patch tested with 0.1% sesquiterpene lactone mix (SL mix) and individual Compositae oleoresins. There were no apparent cases of active sensitization by, or irritancy from, the SL mix. 6 patients had allergic reactions to both SL mix and Compositae oleoresins, while 11 patients had allergic reactions to Compositae oleoresins with a negative reaction to the SL mix. In all but 2 of these, Compositae allergy was considered clinically relevant. As 0.1% SL mix picked up only 35% of cases of Compositae allergy, we do not consider it an adequate screen.     

Routine patch testing with the sesquiterpene lactone mix in Europe: a 2-year experience. A multicentre study of the EECDRG

To test the screening value of the sesquiterpene lactone (SL) mix in Europe today and describe epidemiological and clinical features of Compositae-sensitive patients, the SL mix 0.1% pet. was included in the standard patch test series in 11 European clinics. 10,695 patients were tested, and 106 (1%) had positive reactions, 74% of which were of current or old relevance. The prevalence of positive reactions varied between 0.1 and 2.7% in different centres. The median age of the 66 females was 51.5 years, and 55.2 in the 40 males. The 20 occupationally sensitized had a higher % of males and a median age of 43 years, whereas 7 UV-sensitive patients had a median age of 72 years. Garden plants were the major suspected sensitizers and the clinical patterns were partly, in accordance with plant dermatoses in general, involving hands, forearms and face, and partly widespread eczema in a large proportion of the patients. More than 1/3 were positive to perfume and/or colophony, possibly reflecting cross-reactivity. With only 1 case of active sensitization and no irritant reactions, the SL mix is a safe allergen and the overall prevalence of positive reactions supports its continued use in the standard patch test series.     

Sesquiterpene lactone mix contact sensitivity and its relationship to chronic actinic dermatitis: a follow-up study

In a retrospective case note analysis over a 4-year period, 0.9% of all patients tested with a standard patch test series (65 of 7600) were demonstrated to have clinically relevant responses to a sesquiterpene lactone (SQL) mix. Of these patients, 11 (17%) also had a diagnosis of chronic actinic dermatitis. This group made up 25% of all patients diagnosed as suffering from CAD in this 4-year period. These figures differ somewhat from those reported by our group in an initial 4-year period immediately following the introduction of the mix into our standard patch test series, when 1.5% of all patients tested had a clinically relevant response to the SQL mix, including 36% of all patients with a diagnosis of CAD. It is not uncommon for the prevalence of sensitivity to an allergen to be overestimated immediately following its introduction into routine testing. Possible reasons for our findings are discussed.     

Routine patch testing with frullanolide mix: an European Environmental and Contact Dermatitis Research Group multicentre study

Contact sensitivity to plants containing 1 or more sesquiterpene lactones (SLs) is difficult to diagnose. The mixture of SLs (SL mix) has been shown to detect only about 60% of sensitized individuals. In order to improve the diagnosis of sensitization to plants containing SLs, we have tested a mixture of frullanolides contained in Frullania dilatata and Frullania tamarisci at 3 different concentrations (0.01%, 0.033% and 0.1% in petrolatum). 8605 consecutive eczema patients in 1 North American and 15 European dermatology departments were tested with this mix, and 0.35% of positive cases to the different concentrations were found. Routine use of this mix permitted detection of only a small percentage of extra cases and did not improve the SL mix score. The frullanolide mix should therefore be restricted to investigations in particular geographical zones and/or in particular occupations.     

Recalcitrant atopic dermatitis due to allergy to Compositae

Atopic dermatitis is often complicated by allergic contact dermatitis, although patch testing may reveal positive reactions of uncertain relevance. We report a case of a 35-year-old woman with recalcitrant atopic dermatitis, with a positive patch-test reaction to Compositae mix (CM). Initially, sensitization appeared to be of past relevance only, due to use of calendula. However, it turned out that she followed a self-devised diet consisting largely of food products of the Compositae family. On excluding these food products her skin condition improved quickly. This case report underscores the difficulty in determining the relevance of positive patch tests, and shows that thorough analysis of positive patch tests, by both patient and physician, may reveal unexpected or less common sources of contact allergens.     

Sesquiterpene lactone contact sensitivity: clinical patterns of Compositae dermatitis and relationship to chronic actinic dermatitis

A mix of 3 sesquiterpene lactones (SL) (SL mix 0.1%) was evaluated over a 4-year period, Of 7420 patients with eczema investigated by patch testing. 135 (68 male, 67 female) (1.8%) demonstrated positive reactions, 114 (84%) considered clinically relevant. Females outnumbered males until the age of 60, after which men were more commonly affected. The clinical patterns varied from patients presenting with generalized eczema (20%) or eczema of the hands and face (24%). to patients with hand (36%) or facial eczema (11%) alone. 48 patients were investigated for suspected photosensitivity and 29 (21 male, mean age 69 years, and 8 female, mean age 66 years) had abnormal cutaneous monochromatic irradiation tests. These results highlight the varied clinical presentation of SL contact dermatitis and its association with chronic actinic dermatitis. The SL mix proved reliable and safe, supporting its inclusion in the European standard series of contact allergens.     

An 8-year experience with routine SL mix patch testing supplemented with Compositae mix in Denmark

Routine patch testing with sesquiterpene lactone (SL) mix, supplemented with Compositae mix (CM) and other Compositae extracts and allergens where appropriate, was evaluated over an 8-year period. 190 of 4386 patients tested (4.3%) were Compositae-sensitive, 143 females (mean age 51.5 years) and 47 males (mean age 55 years), and 83% of reactions considered clinically relevant. 22% were suspected of occupational sensitization/dermatitis. 62% had a contact allergy to 2 or more compounds, most often to nickel, fragrance and colophonium. SL mix detected 65%, CM 87% of Compositae-allergic patients, and the overall detection rate with both mixes was 93%. Few irritant reactions and no cases of clear-cut active sensitization were recorded with the mixes, but our results emphasize the importance of differentiating late-appearing reactivation reactions from patch test sensitization. The weakly positive CM reactions could reflect some irritancy, but as they were associated with fragrance and/or colophonium allergy to a higher degree than weakly positive SL mix reactions, they probably represented cross-reactions. In conclusion, the detection rate with SL mix was high enough to support its continued use as a screening mix and it was very well and rather safely supplemented by aimed testing with CM.     

Screening for Compositae sensitization with pure allergens: implications of molecular structure, strength of reaction, and time of testing

Background. The sesquiterpene lactone (SL) mix is the only commercial Compositae allergy screening agent that consists of pure allergens; its detection rate is lower than that of Compositae plant extracts. Objective(s). To report a 15‐year experience with routine screening with SL mix and another allergen, parthenolide, the optimal reading times when testing with SL mix constituents, and the advantages and drawbacks of using pure allergens. Materials and methods. The SL mix 0.1% and parthenolide 0.1% petrolatum were included in the baseline series. Results. Of individuals undergoing routine testing, 157/7163 (2.19%) tested positive to SL mix, 161/7162 (2.25%) to parthenolide, and 141 to both in the 15‐year period. The overall detection rate between the two was 177 persons, and 10% would have been missed without parthenolide testing. Two cases of possible active sensitization to parthenolide were recorded. Costunolide elicited positive reactions most frequently, followed by dehydrocostus lactone, and alantolactone. An important observation was that the prevalence of positive reactions to SL mix constituents was lower if they were applied 3–5 days after application of SL mix in those with 1+ or 2+ reactions. Conclusions. The benefit of detecting 10% more Compositae‐sensitive patients with parthenolide in the baseline series must be weighed against a small risk of active sensitization, which may be reduced by lowering the test concentration.     

A study of the sensitization rate to sesquiterpene lactone mix in Singapore

We report a study of the sensitization rate to sesquiterpene lactone (SL) mix at the National Skin Centre, Singapore. This is a retrospective review of 1256 patients who were patch tested to SL mix (0.1%) from January 1995 to December 1997. 18 out of 1256 patients (1.43%) reacted positively to SL mix. Their ages ranged from 13 to 58 years (average 33.8 years). There were 15 Chinese, 2 Indian and 1 Malay patients. There was a female preponderance, with a female: male ratio of 3.5:1. The most common clinical presentation were dermatitis of the hands (8; 44%), face (5; 28%), and generalized involvement (5; 28%). After extensive evaluation, only 2 patients had a positive patch test reaction that was of current clinical relevance. 13 patients had concomitant sensitization to other allergens. The 3 commonest concomitant allergens were nickel, balsam of Peru and fragrance mix. In our series, SL allergy is observed to be more common in females and the mean age is lower compared to the classical Compositae dermatitis. The sensitization rate is comparable to other studies, although the clinical relevance is only 11%.     

Sesquiterpene lactone mix as a diagnostic tool for Asteraceae allergic contact dermatitis: chemical explanation for its poor performance and Sesquiterpene lactone mix II as a proposed improvement

Background. Two preparations are currently in use for the diagnosis of allergic contact dermatitis caused by Asteraceae: (i) Sesquiterpene lactone (SL) mix [three pure sesquiterpene lactones (STLs)], whose use has been questioned, owing to an insufficient rate of true‐positive results; and (ii) Compositae mix, consisting of five Asteraceae extracts, which is problematic because of lack of standardization and questionable reproducibility. Objectives. To analyse the reasons for the narrow sensitivity of SL mix from a chemoinformatic point of view, and to propose a solution by rational selection of alternative constituents for a new SL mix II covering a broader cohort of allergic patients. Materials/methods. Structural and biological information on allergenic STLs was retrieved from databases and the literature, and molecular modelling and chemoinformatic computations were performed. Results. An explanation for the insufficient hit rate of SL mix is that the three constituents possess extremely similar molecular structures/properties and do not represent well the structural diversity of allergenic STLs. STLs that are known as constituents of Compositae mix plants show much a wider diversity, which explains the higher positive rate. Conclusions. On the basis of their positions in chemical property space, a new collection of STLs that more evenly cover the overall structural diversity spectrum is proposed. SL mix II is likely to detect a larger number of patients sensitized to Asteraceae.     

Airborne contact dermatitis from Frullania

7 subjects, each giving a history of scaly or vesicular dermatitis in light-exposed areas after going for strolls to the park, the forest or the country during warm weather, were evaluated. Patch testing was carried out with Frullania dilatata and Frullania tamarisci as well as with 2 common members of the Compositae and to alantolactone and the sesquiterpene lactone mix. All the patients were positive to F. dilatata , 3 reacted to F. tamarisci as well, and 2 to florists' chrysanthemum. All of them except 1 gave positive responses to the sesquiterpene lactone mix, but only 3 reacted to alantolactone. Airborne contact dermatitis from these species of Frullania was considered to be the cause of their eczema, Patch testing with the sesquiterpene lactone mix seems to be a good screen for Frullania sensitivity; however, a variable pattern of response to these sesq uiterpene-lactone-containing materials was observed, suggesting individual immunologic responses to them.