close encounters with the environment

Botanical Briefs: The Scourge of — hysterophorus L. Thomas W. McGovern, MD Steven LaWarre, BS

Clinical Importance Cutaneous Manifestations Parthenium hysterophorus caused a fair Typically, a single area of the body de- amount of allergic contact dermatitis in velops an acute allergic contact der- the southern United States in the mid- matitis following exposure. With time, dle part of the 20th century, but with however, a more widespread eruption the mechanization of agriculture, its in- develops that may even involve unex- cidence has decreased. Unfortunately, posed sites. The eyelids, melolabial P hysterophorus has become a major folds, retroauricular sulci, and antecu- health and agricultural problem in bital fossae are generally involved and India because of its allergenicity, ag- give the impression of an airborne con- gressiveness, and prolific growth. tact dermatitis. A chronic, lichenified, eczematous, and intensely pruritic Dr. McGovern is in private practice in Fort eruption eventually develops on all ex- Wayne, Indiana, and Mr. LaWarre is from Meijer posed areas, including the face, neck, Botanical Gardens, Grand Rapids, Michigan. Reprints: Thomas W. McGovern, MD, Fort forearms, and dorsal hands. For the first Wayne Dermatology, PC, 1234 E Dupont Rd , few years, the dermatitis flares in the Suite 6, Fort Wayne, IN 46825. summer, during the ’s growing sea-

FIGURE 1. Parthenium hysterophorus (pho- tographed at Kew Gardens, England).

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son, and disappears in the winter. How- “Congress weed” is a reference to the ever, if the condition remains un- US Congress that legislated the wheat treated for several years, a persistent, donation.2 In India, P hysterophorus pruritic, lichenified dermatitis devel- found an inviting ecologic niche with- ops.1;2 One example of a photocontact out natural enemies and spread rapidly dermatitis due to exposure to along canal banks, roads, and railways, P hysterophorus has been reported.3 developing into a major field weed.1 There is a high frequency of photo- sensitivity in patients with Compositae/ Dermatitis-Inducing Plant Parts sesquiterpene lactone (SQL) allergy, Flowers and leaves are more potent even though SQLs possess neither pho- sensitizers than stems.6 The mechanism totoxic nor photoallergic properties.1 by which an airborne contact dermati- Frain-Bell and Johnson reported that tis pattern occurs remains a mystery. 47 of 55 patients (85%) with chronic photosensitivity dermatoses had posi- Nomenclature tive patch tests to Compositae.4 P hysterophorus L. has many epithets, In India, more adult males are af- including feverfew, wild feverfew, bas- fected by Parthenium dermatitis than tard feverfew, wild wormwood, white- adult females or children, even though top, whitehead, white broomweed, exposure is similar for all groups.1 Early pound-cake bush, dog-flea weed, carrot studies estimated a ratio of 20:1 be- weed, Congress weed, Congress grass, tween men and women.2 This may be and the “scourge of India.” The com- caused by the fact that Indian women mon names feverfew and wormwood have less exposed skin.2 An Indian have been applied to other unrelated study of 45 men and 15 women with plant species. SQL allergy found that 41 of the men (91%) and 7 of the women (47%) Identifying Features/Plant Facts reacted to plant material from P hysterophorus is an annual herb with a P hysterophorus.5 This study showed a deep taproot and an erect stem that be- surprisingly low rate of cross-reactivity comes woody with age. Leaves are deeply to various Composites. Of the 60 par- dissected, alternate, pale green, and cov- ticipants, 47 (78%) reacted to ered with soft fine hair (Figure 1). Flow- P hysterophorus, 25 (42%) reacted to a ers are creamy white and possess inner Chrysanthemum species, 11 (18%) re- tubular florets and outer ray florets. acted to Dahlia pinnata, and 4 (7%) re- acted to Tagetes indica (marigold). Allergens Thirty-five of the participants (58%) Parthenin, an SQL, is considered to be responded to only 1 of the 4 Composi- the major allergen of the species. A num- taes used. ber of other SQLs also have been iso- lated, including ambrosin, hymenin, Family coronopilin, hysterin, and tetraneurin A. P hysterophorus belongs to the family Unlike the South American Compositae (or ), one of the P hysterophorus, the Indian plant con- largest families of flowering con- tains large amounts of the SQLs taining about 13,000 species, including parthenin and ambrosin.1 the daisy and the sunflower. Treatment Distribution of Plant Potent topical steroids and oral pred- Although indigenous to the Americas nisone are relatively ineffective unless and the Caribbean region, this aggres- employed early (before year-round sive weed has spread in the last dermatitis occurs) and unless further 100 years to Australia, Africa, and exposure to SQLs is prevented. Asia. In 1956, it was accidentally trans- Azathioprine in a dose of 2 mg/kg per ported to Poona, India, in a consign- day may be helpful, even in protracted 1 ment of US wheat. In fact, the epithet CONTINUED ON PAGE 34

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CONTINUED FROM PAGE 28 cases of dermatitis.7 This treatment regimen depresses both T-suppressor cells and Langerhans’ cells. An Indian physician who treats many cases of Parthenium dermatitis uses chloroquine, 200 mg, 3 times daily for 1 week and then tapers it.8 He also uses 0.05 mg ethinyl estradiol in both adult men and women and tapers it after 3 weeks. He bases his use of estrogen on the fact that, in his experience, only postmenopausal women are affected by this condition. Whole body mechlorethamine (nitrogen mustard) is effective, but only temporarily, and cyclosporine works only as long as the patient continues to take it.9 Methotrexate and nicotinic acid are not effective in the treatment of Parthenium dermatitis.9

REFERENCES 1. Warshaw EM, Zug KA. Sesquiterpene lactone allergy. Am J Contact Dermat. 1996;7:1-23. 2. Guin JD. Sesquiterpene-lactone dermatitis. Immunol Allergy Clin North Am. 1989;9:447-461. 3. Bhutani JK, Rao DS. Photocontact dermatitis caused by Parthenium hysterophorus. Dermatologica. 1978;157:206-209. 4. Frain-Bell W, Johnson BE. Contact allergic sensitivity to plants and the photosensitivity dermatitis and actinic retic- uloid syndrome. Br J Dermatol. 1979;101:503-512. 5. Sharma SC, Kaur S. Airborne contact dermatitis from Com- positae plants in northern India. Contact Dermatitis. 1989;21:1-5. 6. Sharma SC, Tanwar RC, Kaur S. Contact dermatitis from chrysanthemums in India. Contact Dermatitis. 1989;21:69- 71. 7. Srinivas CR, Balachandran C, Shenoi SD, et al. Azathio- prine in the treatment of Parthenium dermatitis. Br J Der- matol. 1991;124:394-395. 8. Fisher AA. Esoteric contact dermatitis. part IV: devastating contact dermatitis in India produced by American Parthenium weed (The scourge of India). Cutis. 1996;57:297- 298. 9. Burke DA, Corey G, Storrs FJ. Psoralen plus UVA protocol for Compositae photosensitivity. Am J Contact Dermat. 1997;7:171-176.

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