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Wedelia - Zinnia

(Daisy or Sunflower family)


Wedelia rugosa Greenman

Ivalin, a potentially allergenic eudesmanolide, has been reported from this species.

Wyethia Nutt.

Fourteen species occur in western North America. The genus is classified in the tribe Heliantheae.

Wyethia helenoides Nutt.

6-Desoxyperozone, a potentially allergenic sesquiterpenoid derivative of 1,4-benzoquinone, has been reported from this species (Bohlmann et al. 1981n).

Xanthium L.

This genus is classified in the tribe Heliantheae. Thirty species are of cosmopolitan distribution, having been unintentionally spread by animals and by man. The hooked fruits become attached to animal hair; sheeps wool that is contaminated with the burs loses its value.

The burs and the spines on the stems of some species can cause mechanical injury.

Fourteen of 25 patients who had "weed dermatitis" showed positive patch test reactions to an extract of a Xanthium species (Mackoff & Dahl 1951). Rook (1962) observed an individual who was contact sensitive to Xanthium, Chrysanthemum L., and other members of the Compositae.

Potentially allergenic sesquiterpene lactones have been reported from the following species:

Xanthium chasei Fern.
Xanthium commume Britton
Xanthium occidentale Bertol.
Xanthium orientale L.
Xanthium pensylvanicum Wallr.
Xanthium riparium Lasch 

Other species are considered in the monographs below.

Xanthium canadense Mill.

Brunsting & Anderson (1934) and Brunsting & Williams (1936) reported contact sensitivity to this plant and to other members of the Compositae in about one fifth of 32 patients who had "weed dermatitis".

Xanthodiene, a potentially allergenic eremophilanolide, has been reported from this species.

Xanthium occidentale Bertol.

The burs of this species can cause mechanical injury to cattle, and spoil sheeps' wool. When ingested, they can cause intestinal obstruction; ingestion of the mature plant can cause a fatal syndrome in cattle, producing fever, dermatitis, and black faeces (Watt & Breyer-Brandwijk 1962).

Xanthium pungens Wallr.

This species can cause mechanical injury to animals. Handling the plant was said to have caused pruritus, erythema, urticaria, and angioneurotic oedema in a person in South Africa who had evidently become allergic to it (Watt & Breyer-Brandwijk 1962).Gardner & Bennetts (1956) include this species in a list of plants known or suspected of causing dermatitis.

Xanthium spinosum L.
Bathurst Burr, Cocklebur

The plant is spiny and the fruit bears burs with hooked hairs. It can cause mechanical injury of the skin (Wimmer 1926, Watt & Breyer-Brandwijk 1962). Its spines are a nuisance to pickers of hand-harvested crops (Bull & Burrill 2002).

Rowe (1939) reported two cases of dermatitis from the plant, with positive patch test reactions to the leaf and, to a lesser extent, to the pollen and also to Artemisia californica Less. and Artemisia vulgaris L. Four patients from 13 who had "Australian bush dermatitis" showed positive patch test reactions to this plant, to Xanthium californicum Greene (see Xanthium strumarium L. var canadense Torrey & A. Gray below), and to other members of the Compositae (Burry et al. 1973).

Xanthatin, a potentially allergenic xanthanolide, has been reported from this species.

Xanthium strumarium L.
Noogoora Burr

The plant is rough to the touch and causes itching from the hairs or dust with which it is covered (Cheney, cited by White 1887). The burs, if ingested, cause mechanical irritation of the mouth (Burkill 1935).

A weeping eczema from handling the plant has been reported (Maiden 1918a, Maiden 1921, Cleland 1925), as has dermatitis in men working among the plants (Hurst 1942). Patch tests carried out using the leaves of this species crushed in a small quantity of normal saline elicited positive reactions in 7 of 24 contact dermatitis patients tested in New Delhi, India (Singh et al. 1978). Cross-reactions to Parthenium hysterophorus were not observed.

Frain-Bell & Johnson (1979) observed positive patch test reactions to the oleoresin from this species in 21 from 55 patients with the photosensitivity dermatitis and actinic reticuloid syndrome.

Several potentially allergenic xanthanolides have been reported from this species. Winters et al. (1969) noted the existence of chemical races within this taxon, and also that Xanthium pensylvanicum Wallr. is morphologically indistinguishable from Xanthium strumarium.

Xanthium strumarium L. var canadense Torrey & A. Gray
(syns Xanthium californicum Greene, Xanthium canadense Mill., Xanthium echinatum Murray, Xanthium italicum Moretti, Xanthium speciosum Kearney, Xanthium strumarium L. ssp italicum D. Löve)
Californian Burr, Canada Cocklebur

Four patients from 13 who had "Australian bush dermatitis" were contact sensitive to this taxon and to some other members of the Compositae (Burry et al. 1973). The cross-sensitivity pattern was not identical in the four cases.

Zaluzania Pers.

This is a genus of 12-15 species found in Mexico.

Potentially allergenic sesquiterpene lactones have been reported from the following species:

Zaluzania augusta Schulz-Bip.
Zaluzania montagnaefolia Schulz-Bip.
Zaluzania pringlei Greenman
Zaluzania robinsonii W. Sharp
Zaluzania triloba Pers. 

Zinnia L.

Twenty species are found in the southern United States through to Brazil and Chile. Many varieties and cultivars of Z. elegans Jacq. are cultivated in Europe for their decorative flowers.

Shelmire (1939a) reported a species of this genus as a minor skin sensitiser, but gave no clinical details.

Potentially allergenic sesquiterpene lactones have been reported from the following species:

Zinnia haageana Regel
Zinnia peruviana L.
(syns Zinnia multiflora L., Zinnia pauciflora L.) 

Zinnia elegans Jacq.
Youth and Age

This species was listed among plants that could cause contact dermatitis (McCord 1962). Hausen (1981b) and Hausen & Osmundsen (1983) observed positive patch test reactions to an extract of this species in patients with contact dermatitis from Tanacetum parthenium Schulz-Bip.

Zinnia pauciflora L.

This species was suspected as a cause of photosensitisation following ingestion by animals (Hurst 1942).


Although Compositae dermatitis has previously been regarded as a North American problem, it is now known to occur in Europe, Australia, India, and elsewhere.

The most important clinical pattern of dermatitis from members of the Compositae is "weed dermatitis". Adult males are most frequently affected by dermatitis that affects exposed skin surfaces not ordinarily covered by clothing; it is at first seasonal, but later may become perennial. Such allergic contact dermatitis is usually chronic and indurated or lichenified, with marked chronicity although acute exacerbations are frequent. Vesicular or bullous dermatitis is rarely observed, the clinical picture of chronic cases of "weed dermatitis" resembling atopic dermatitis and photodermatitis (Mitchell 1969, Lonkar et al. 1974). Patch test reactions to compositaceous plants in sensitised individuals are frequently severe, vesicular or bullous, and persistent. Patients often react to other members of the family. It has been alleged that atopic individuals are particularly prone to "weed dermatitis", and that photosensitivity can develop. The data suggest that eczematous skin, whether atopic or not, is particularly prone to "weed dermatitis" and that sunlight induces photo-irritation of dermatitic skin (Lonkar et al. 1974). The role of pollen is probably minimal; airborne dried plant material, and weed oleoresin-contaminated fomites can cause, maintain, and aggravate "weed dermatitis" (Lonkar et al. 1974, Howell 1978, Mitchell 1981c). The predilection for middle-aged males, the rarity of affection of females, and the sparing of children are unexplained.

Another clinical pattern of Compositae dermatitis is an eczema of the hands from handling the plants, particularly chrysanthemums and salad plants.

The clinical pattern of Compositae dermatitis may be that of a lichenified photodermatitis. These cases are invariably missed unless patch tests with members of the Compositae are carried out. There is a certain amount of confusion in the literature regarding photodermatitis and certain manifestations of sesquiterpene lactone dermatitis. The occurrence of photosensitivity or a simulated photosensitivity is periodically reported in the literature (Hand 1944, Fromer & Burrage 1953, Epstein 1960, Tan & Mitchell 1968, Mitchell et al. 1970, Hjorth et al. 1976). It is now clear that sesquiterpene lactone dermatitis can simulate photodermatitis when it is a result of contact with an airborne source of the lactones. This would appear to be the manner in which Australian bush dermatitis, ragweed dermatitis, and parthenium dermatitis are all produced. Calnan (1978a) recommends the inclusion of a chrysanthemum leaf in a photoallergen series in order to detect Compositae dermatitis simulating photodermatitis. An alternative aetiology would be a phototoxic or photoallergic reaction to an airborne source of the lactones (or indeed other dermatologically active materials). This would produce a true contact photodermatitis, which would only be observed on skin that had been in contact with the offending material and had been then exposed to the appropriate wavelength of light. This is at least a theoretical possibility, but there is very little clinical evidence to support it (Crounse 1980). A third, and least understood, possibility is that of the sesquiterpene lactones producing the chronic photosensitivity state known as "photosensitivity dermatitis and actinic reticuloid syndrome" in which any part of the skin, whether it has or has not previously been exposed to (for instance) an airborne source of sesquiterpene lactones, will react idiopathically to particular wavelengths of visible and/or UV light. Present evidence (Frain-Bell et al. 1979, Frain-Bell & Johnson 1979) does not answer the question as to whether or not sesquiterpene lactones produce the syndrome but demonstrates clearly that such patients are commonly contact sensitive to extracts from members of the Compositae.

Photosensitivity to members of the Compositae was discussed by Crounse (1980) and by Arlette & Mitchell (1981).

Hausen (1977) described a rapid and convenient method of extracting sesquiterpene lactones from members of the Compositae for the preparation of patch test materials. The method involves a brief (30-60 second) immersion of whole leaves in purified ether - a so-called "short ether extract" - which is then dried over anhydrous sodium sulfate, and the ether evaporated. The residue may then be dissolved in either acetone or ethanol (10% w/v) or dispersed in petrolatum (1% w/v).

Reports of specific hyposensitisation by administration of Ambrosia extracts have rarely included evidence by quantitative patch testing. In such a study, Fisher (1952) reported success by the oral route. Spontaneous desensitisation was not observed. Some other references to hyposensitisation in Ambrosia dermatitis were recorded by Mitchell (1969).

Richard J. Schmidt [Valid HTML 4.01!]

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