Patch testing with the "sesquiterpene lactone mix": a marker for contact allergy to Compositae and other sesquiterpene-lactone-containing plants. A multicentre study of the EECDRG

The sesquiterpene lactone mix: A review of past, present and future aspects

The sesquiterpene lactones (SLs) are secondary plant metabolites, which are widespread in the Compositae/Asteraceae plant family. The first SLs were detected more than 100 years ago, and allergic contact dermatitis from Compositae has been reported since the beginning of the 1900s, but it was not until the late 1960s and early 1970s that a collaboration between dermatologists, chemists and botanists led to the detection of SLs as the main allergens of Compositae plants. In the 1980s, the SL mix, consisting of equimolar amounts of alantolactone, costunolide and dehydrocostus lactone, was developed as a screening agent for Compositae sensitisation. Today, after inclusion of SL mix in the baseline series, the mean prevalence of reactions in Europe is around 1%, and in North America 0.8%. In countries outside Europe and North America, the prevalence ranges between 0% and 10.7%. The detection rate of SL mix is lower than that of some plant extracts, and ideally, SL mix should be supplemented with a mix of SLs from locally prevalent allergenic plants. The prevalence of positive reactions to SL mix suggests continued baseline testing in most European countries, North America, New Zealand, Australia and probably some Chinese centres.

Effects of diet on skin sensitization by nickel, poison ivy, and sesquiterpene lactones

Skin contact or exposure to sensitizers often occurs as a consequence of occupational exposures (e.g. poison ivy in forestry), wearing jewelry (e.g. nickel), or use of cosmetics (e.g. fragrances). However, many of the known skin sensitizers or their chemical variants are also consumed orally through foods or other sources. Since oral exposure to antigenic substances can lead to tolerance, consumption of sensitizers may impact the development and potency of skin sensitization, especially if the sensitizer is consumed early in life, prior to the first skin contact. To address this issue, we have reviewed human clinical and epidemiological literature relevant to this subject and evaluated whether early oral exposures to relevant sensitizers, or their chemical variants, are associated with reduced prevalence of skin sensitization to three main allergic sensitizers - nickel, urushiols of poison ivy, and sesquiterpene lactones of chrysanthemum and other plants.

Contact dermatitis as an adverse reaction to some topically used European herbal medicinal products - part 4: Solidago virgaurea-Vitis vinifera

This review focuses on contact dermatitis as an adverse effect of a selection of topically used herbal medicinal products for which the European Medicines Agency has completed an evaluation up to the end of November 2013 and for which a Community herbal monograph - now (since 2014) called a 'European Union herbal monograph' - has been produced. The present part 4 addresses species from Solidago virgaurea L. to Vitis vinifera L.

Identification of a compound isolated from German chamomile (Matricaria chamomilla) with dermal sensitization potential

German chamomile is one of the most popular herbal ingredients used in cosmetics and personal care products. Allergic skin reactions following topical application of German chamomile have been occasionally reported, although it is not fully understood which of the chemical constituents is responsible for this adverse effect. In the present work, three candidate sensitizers were isolated from German chamomile based on activity-guided fractionation of chamomile extracts tested using the in vitro KeratinoSens™ assay. The compounds were identified as the polyacetylene tonghaosu (1), and both trans- and cis-glucomethoxycinnamic acids (2 and 3). These three compounds were classified as non- to weakly reactive using in chemico methods; however, aged tonghaosu was found to be more reactive when compared to freshly isolated tonghaosu. The polyacetylene (1) constituent was determined to be chemically unstable, generating a small electrophilic spirolactone, 1,6-dioxaspiro[4.4]non-3-en-2-one (4), upon aging. This small lactone (4) was strongly reactive in both in chemico HTS- and NMR-DCYA methods and further confirmed as a potential skin sensitizer by Local Lymph Node Assay (LLNA).

Allergic contact dermatitis to plants: understanding the chemistry will help our diagnostic approach

Allergic contact dermatitis due to plants is common. Potentially allergenic plants and plant products are found in many everyday environments, such as the home, the garden, the workplace, and recreational settings. By improving our knowledge of allergenic plant-derived chemical compounds, we will be better positioned to identify novel allergens. We review the most relevant chemical allergens that contribute to plant allergic contact dermatitis and propose a clinical classification system based on 5 major families of chemical sensitizers: α-methylene-γ-butyrolactones, quinones, phenol derivatives, terpenes, and miscellaneous structures (disulfides, isothiocyanates, and polyacetylenic derivates). We also describe the different clinical pictures of plant allergic contact dermatitis and review currently available patch test materials. A better understanding of the specific allergens involved in plant allergic contact dermatitis will help to predict cross-reactivity between different plant species or families.

Allergic contact dermatitis to plants in a Spanish dermatology department: a 7-year review

To investigate the incidence of allergic contact dermatitis (ACD) to plants in our area, we reviewed the records of the patients that were studied in the Allergic Contact Unity of our hospital in the last 7 years (2248 patients). We found 69 cases of positive patch tests to plant allergens, representing 3% of all the patients in that period. Diallyl disulfide was the most frequent allergen (47 cases), involving mainly middle-aged housewives with chronic hand eczema. Positive tests to sesquiterpene lactone mix (SL mix) were found in 11 patients, mostly middle-aged rural workmen with an airborne clinical pattern. Other allergens detected were lichens, primin, tulipalin A and wood. These results show a high incidence of ACD to diallyl disulfide that, in our opinion, should be tested in all housewives or cooks with chronic hand eczema. The predominance of the classical airborne pattern of allergy to SL in our study may be because the airborne way of allergen exposure in our area, with a high percentage of rural population, is the most frequent, and it makes it important to remember this possibility in the differential diagnosis of photosensitivity.

[Is Vojvodina a risk area for contact weed allergies?]

INTRODUCTION

After detecting erythema multiforme due to contact with weeds, dandelion (Taraxacum officinale, Compositae) and common chickweed (Stellaria media, Caryophyllaceae), which are ubiquitous plants in Vojvodina, and concerning properties of commercial screening allergens in detection of allergy to plants, we investigated contact allergy to dandelion and to common chickweed, using their extracts.

MATERIAL AND METHODS

Epicutaneous tests were performed using originally prepared ether extracts of these plants, 0.1% and 3% pet., in 263 individuals: 43 with extrinsic atopic dermatitis, 55 with allergic contact dermatitis, 118 with non-allergic chronic inflammatory skin diseases and 47 healthy adults.

RESULTS

Our results have shown that testing with both extracts (both concentrations) represents a safe method, since no irritation or sensibilization occurred. The overall prevalence of allergy to dandelion extract was 1.14%, and for common chickweed extract 2.28%.

DISCUSSION

Plant allergies (especially Compositae) cannot always be detected by standard screening allergens. Additional testing with dandelion extract can detect most cases, which is in agreement with our results. Isolation of essential oil from common chickweed proved the allergenic potential of this plant. The prevalence of detected allergy to dandelion as well as to common chickweed was higher than 1%.

CONCLUSION

These ubiquitous weeds and high prevalence of detected allergies have included Vojvodina into a risk zone for getting contact sensitivity to dandelion and common chickweed. Dandelion extract should be considered for Compositae screening series and common chickweed extract for specific plant series in Vojvodina.

Étude prospective multicentrique 1991-2001 de la batterie standard des photopatch-tests de la Société Française de Photodermatologie

INTRODUCTION

To develop a standard panel of photopatch tests, the French Society of Photodermatology conducted a prospective study from 1991 to 2001 on the frequency of photoallergens encountered in France and on the relevance of the choice of the various photoallergens.

PATIENTS AND METHODS

Thirteen photobiology centers participated in the study from 1991 to 1995, and ten centers from 1995 to 2001. A set of 3 samples of photopatch tests was applied on any patient suspected of photoallergy. On Day 2, two sets were irradiated with ultraviolet A (UVA) and total spectrum (DEM 0.75); with the third set being used as control. Readings were made on D3 and D4.

RESULTS

Two thousand sixty-seven patients were tested. Eight hundred fifty-six, i.e., 41% exhibited one or several positive tests. In the majority of cases it was a photoallergy (39.7 to 60% of cases) and eczema (29.5 to 45.6%). Photoaggravation was infrequent (7.9 to 10.3%). Cases of phototoxicity were rare. Sesquiterpenic lactones constantly provoked photoallergy, with 12 cases in 10 years. Although phenothiazines were the most photosensitizing allergens up until 1995, they were then overridden by ketoprofen in 1996 with 107 cases of UVA photosensitive reactions (75 cases) and total spectrum (32 cases). These were followed closely by sun screens, benzophenone (notably Eusolex 4360 with 54 pertinent cases of photoallergy) and dibenzoylmethane (with 31 cases due to Eusolex 8020). UVB filters were all potentially photosensitizing but to a lesser degree from 1 to 5 cases).

DISCUSSION

Our results differ from those of Anglo-Saxon teams in the appearance of a new photoallergen, ketoprofen, which provoked numerous photosensitivities in both UVA and UVB. This justifies the systematic addition of this substance in our prospective set. Photoallergy was relatively rare, with around 100 cases reported within 10 years. Total spectrum irradiation of the photopatch tests revealed photoallergies that would not have been found with UVA alone.

CONCLUSION

Study of photopatch tests has permitted the uniformization of the methodology in France, an overview of the frequency of the photoallergens tested and the development of a new standard set.

Sesquiterpene lactone mix patch testing supplemented with dandelion extract in patients with allergic contact dermatitis, atopic dermatitis and non-allergic chronic inflammatory skin diseases

We investigated the value of patch testing with dandelion (Compositae) extract in addition to sesquiterpene lactone (SL) mix in selected patients. After we detected a case of contact erythema multiforme after patch testing with dandelion and common chickweed (Caryophyllaceae), additional testing with common chickweed extract was performed. A total of 235 adults with a mean age of 52.3 years were tested. There were 66 men and 169 women: 53 consecutive patients with allergic contact dermatitis (ACD); 43 with atopic dermatitis (AD); 90 non-atopics suffering from non-allergic chronic inflammatory skin diseases; 49 healthy volunteers. All were tested with SL mix 0.1% petrolatum (pet.) and diethyl ether extracts from Taraxacum officinale (dandelion) 0.1 and 3.0% pet. and from Stellaria media (common chickweed) 0.1 and 3% pet. A total of 14 individuals (5.9%) showed allergic reaction (AR) to at least 1 of the plant allergens, 4 (28.6%) to common chickweed extract, and 11 (78.6%) to Compositae allergens. These 11 persons made the overall prevalence of 4.7%: 8 (3.4%) were SL-positive and 3 (1.3%) reacted to dandelion extract. 5 persons (45.5%) had AD, 2 had ACD, 2 had psoriasis and 2 were healthy controls. The Compositae allergy was relevant in 8 cases (72.7%). The highest frequency of SL mix sensitivity (9.3%) was among those with AD. Half the SL mix-sensitive individuals had AD. ARs to dandelion extract were obtained only among patients with eczema. A total of 9 irritant reactions (IRs) in 9 individuals (3.8%) were recorded, 8 to SL mix and 1 to common chickweed extract 3.0% pet. No IR was recorded to dandelion extract (P = 0.007). Among those with relevant Compositae allergy, 50.0% had AR to fragrance mix and balsam of Peru (Myroxylon pereirae resin) and colophonium. SLs were detected in dandelion but not in common chickweed. Our study confirmed the importance of 1 positive reaction for emerging, not fully established, Compositae allergy. In conclusion, the overall prevalence of 4.7% in our study represents a basal SL mix detection rate of 3.4% reinforced and safely supplemented by testing with the dandelion extract.

Contact allergy to Compositae plants in patients with atopic dermatitis

To investigate the frequency of Compositae sensitivity is one of the most important goals of current dermatology and allergology. We have patch tested 30 adult patients suffering from "extrinsic" atopic dermatitis with sesquiterpene lactone mix and Compositae mix including Compositae mix individual ingredients, extracts of arnica (Arnica montana), chamomile (Chamomilla recutita), tansy (Tanacetum vulgare), fever few (Tanacetum parthenium) and yarrow (Achillea millefolium) as well as with specific series for patients with atopic dermatitis. All allergens were purchased from Hermal-Trolab (Reinbek, Germany). There were 6 (20%) patients positive to Compositae mix only, and 3 (10%) patients positive to both Compositae mix and sesquiterpene lactone mix. Among 9 Compositae mix-sensitive patients 8 (88.8%) were positive to at least 1 of its individual ingredients: 5 (55.5%) to chamomile, 4 (44.4%) to arnica, 2 (22.2%) to tansy, and 2 (22.2%) to fever few. Among Compositae-sensitive patients 78.8% had other contact allergies, most often to nickel (33.3%). Since our study represents the first report on contact allergy to Compositae among patients with "extrinsic" type of atopic dermatitis, it substantiates the statement that atopy represents a risk factor for Compositae allergy. In conclusion, the overall prevalence of 30% Compositae-sensitive among patients with "extrinsic" atopic dermatitis detected in our study represents a basal sesquiterpene lactone mix detection rate of 10%, reinforced and safely supplemented by 20% by testing with the Compositae mix.

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.

[Compositae dermatitis]

INTRODUCTION

Compositae dermatitis is an allergic contact dermatitis caused by plant species of the Compositae family. The first report of a cutaneous reaction to the Chrysanthemum genus was made by Howe JS in 1887. In 1895 Maiden JH reported about skin lesions among men working with Tagetes minuta. Case reports of contact allergic-ragweed dermatitis appeared in the American literature as early as 1919. The North American feverfew--Parthenium Hysterophorus was brought to India from America in 1956 and it caused thousands of cases of so-called parthenium dermatitis. Ragweed and parthenium dermatitis became prototypes for the classic, so-called "airborne" Compositae dermatitis, that affects primarily exposed skin surfaces, and produces a universal erythroderma.

EPIDEMIOLOGY

The frequency of contact allergy to Compositae in Europe is higher than previously believed. It occurs most frequently in middle-aged and elderly persons, but also in all age groups. During the two past decades a more equal sex ratio has been established. The prevalence varies from 0.7-1.4% in the general population, up to 4.5% among occupationally exposed persons. Compositae allergy is among the top ten contact sensitivities in Europe. In North Europe plants were the cause of 4.4% cases of occupational allergic contact dermatitis. ETIOLOGY AND PATHOGENESIS: Among cultivated Compositae plants, Chrysanthemum is considered to be a major sensitizer in Europe (60%). Among the edible types, it is lettuce--Lactuca sativa and endive Cichorium endivia (20-30%), and wild-growing feverfew--Tanace--tum parthenium (70-90%), tansy--Tanacetum vulgare (54%), and dandelion--Taraxacum officinale (65%). Sesquiterpene lactones are the main sensitizers of the Compositae family. Other components, thiophenes and acetylenes are said to elicit only phytophotodermatitis, but recent studies have demonstrated that some thiophenes and benzofuran derivates possess not only phototoxic activity, but also sensitizing properties. Photosensitivity is present in 22-75% Compositae sensitive individuals. Extracts from Compositae are known to be phototoxic in vitro. Photoreactivity of alpha-methylene-gamma-la-ctone group of sesquiterpene-lactone directed towards the DNA base thymine, thus producing intermolecular 2 + 2 photoadducts (antigen within the cell), was also thought to be related to photosensitivity. Clinical manifestations vary from generalized eczema (20-30%), eczema of hands and face (24%), hand (36-44%), or facial eczema (11-28%). 65% of patients have vesicular hand eczema.

DIAGNOSIS

Routine patch testing with sesquiterpene lactone mix, aimed testing with Compositae extracts screening mix, Compositae plants, and with their extracts, whereas the treatment of choice is a specific allergen-immunotherapy.

Contact allergy to the Asteraceae plant Ambrosia artemisiifolia L (ragweed) in sesquiterpene lactone-sensitive patients in southern Sweden

Ambrosia artemisiifolia L. a classical cause of ragweed dermatitis in North America, is also found in Europe. 17 patients with contact allergy to sesquiterpene lactone (SL) mix were recalled for patch testing with extracts of North American and Swedish ragweed, the latter harvested in summer and autumn. 8/17 patients were test-positive to the American extract, 14/17 to the Swedish summer extract and 15/17 to the autumn extract. All patients except 1 were found to have a chronic hand eczema of the pompholyx type. 5/16 hand eczema patients had a flare-up of their pompholyx at patch testing. We concluded that patients with SL mix allergy are allergic to American as well as to Swedish ragweed. Pompholyx seems to be a frequent clinical picture in patients with SL mix allergy.

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.

Thoughts on sensitizers in a standard patch test series. The European Society of Contact Dermatitis

Patch testing is the predominant method of establishing contact allergy. The present patch test technique is the result of a continuous process of development and improvement since its first application in the late 19th century. The perfect patch test should give no false-positive and no false-negative reactions. The ideal patch test should also cause as few adverse reactions as possible, particularly no patch test sensitization. Even though the history and examination of a patient with suspected allergic contact dermatitis will give clues to possible sensitizers, it is not sufficient to patch test only with initially suspected sensitizers; unsuspected sensitizers used for patch testing frequently turn out to be the real cause of the dermatitis. Fortunately, a small number of substances are considered to account for the majority of delayed hypersensitivity reactions. Therefore, generally 20-25 test preparations consisting of chemically defined compounds, mixes of allergens, and natural and synthetic compounds, are grouped into a standard test series. The requirements to be fulfilled by a sensitizer in a standard patch test series are discussed in this article. A procedure of investigations is proposed before a sensitizer is included in a standard series.

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%.

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.

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.

Patch testing for Compositae allergy

The main allergenic constituents of Compositae plants are the sesquiterpene lactones (SLs). In recent years, a mixture of three SLs, each with a different sesquiterpene skeleton (alantolactone, dehydrocostuslactone or costunolide), has been routinely used to detect Compositae allergy. The purpose of our study was to establish the value of testing with a range of Compositae extracts. Ninety-seven consecutive patients with exposure pattern dermatitis or hand eczema and gardening as a hobby or occupation were patch tested to the European standard series including SL mix 0.1% pet., Compositae extracts and other relevant allergens. Twenty-six of the 97 patients tested showed allergic reactions to SL mix or Compositae extracts. Fifteen of these showed positive reactions to both the SL mix and Compositae extracts. Eleven patients showed a negative reaction to the SL mix but positive reaction to the Compositae extracts. Dandelion elicited a positive reaction in eight of the 11 SL mix-negative patients and three patients reacted to feverfew. The SL mix failed to detect 38% of our Compositae-sensitive patients. Dandelion extract alone detected 73% of SL-negative patients. Additional testing with feverfew extract would have detected 91% of the SL mix-negative individuals. Our study highlights the importance of testing the response of SL-negative patients to additional Compositae extracts when there is a clinical suspicion of Compositae allergy.

Comparison of simultaneous patch testing with parthenolide and 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.

Common contact sensitizers in Chandigarh, India. A study of 200 patients with the European standard series

200 patients (122 male, 78 female) with suspected allergic contact dermatitis were patch tested with the European standard series (ESS) and the results compared with other Asian centres. 131 (65.5%) patients showed 1 or more patch test positives to the ESS. Patch tests were positive to all allergens except primin. Potassium dichromate was the most common allergen (20.5%) followed by nickel sulfate (16.5%), SQL mix (14%), PPD (11.5%), cobalt (8%), fragrance mix (7.5%), formaldehyde (6.5%), colophony (5.5%), neomycin sulfate and mercapto mix (5% each). In women, nickel sulfate was the commonest allergen (30.8%) followed by SQL mix (16.7%) and potassium dichromate (15.4%). In men, potassium dichromate was the commonest sensitizer (23.8%) followed by SQL mix and PPD (12.3% each). Our results are at variance with other centres in Asia. SQL mix was able to detect less than 1/2 (42.2%) of patients allergic to ethanolic dilutions of ether extracts of parthenium. We conclude that the European standard series, with exclusion of primin, is suitable for detection of allergic contact dermatitis in India. However, SQL mix is not a adequate screen for parthenium sensitivity and patch testing with extracts of the plant should be continued, wherever indicated.

The European standard series. European Environmental and Contact Dermatitis Research Group (EECDRG)

Changes to the European standard series which have taken place since the last officially recommended alterations in 1988, are explained. New to the series is the sesquiterpene lactone mix. The PPD black rubber mix and the quinoline mix have been replaced by single components; one of the p-hydroxybenzoates has been left out of the paraben mix. Ethylenediamine dihydrochloride has been dropped from the series.

Contact and photocontact sensitization in chronic actinic dermatitis: sesquiterpene lactone mix is an important allergen

Eighty-nine patients with chronic actinic dermatitis (CAD) were retrospectively studied: 69 (78%) male and 20 (22%) female, with mean ages of 66 and 64 years, respectively; nine (10%) were dark skinned. Eight (9%) were abnormally sensitive to UVB wavelengths alone, 74 (83%) to UVB and UVA, and seven (8%) to UVB, UVA and visible radiation. Eighty-six patients were patch tested to an extended standard European series of contact allergens, including in 80 cases a 0.1% mix of three sesquiterpene lactones, and photopatch tested to a standard photopatch series. Sixty-four of these 86 patients (74%) had positive patch or photopatch tests; 36% (29 of 80) were sensitive to the sesquiterpene lactone mix, 21% (18 of 86) to fragrance compounds, 20% (17 of 86) to colophony, and 14% (12 of 86) to rubber chemicals. Ten (12%) had positive photopatch tests; five (6%) to musk ambrette, six (7%) to sunscreens and one to both. Fourteen of the eighty-nine patients with CAD (16%) had preceding endogenous eczema. In 18 of 86 patients (21%), CAD occurred alone, with neither detectable contact nor photocontact allergy, nor a preceding history of endogenous eczema. This study confirms the association between Compositae (sesquiterpene lactone) dermatitis and CAD.

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.

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 sesquiterpene-lactone-containing materials was observed, suggesting individual immunologic responses to them.

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.