Contact Dermatitis from Mango, Poison Ivy, and Other "Poison" Plants

U-RU-SHI-OL (oo roo' shi ol) - from the Japanese; the sap of the lacquer tree. (2)

The Hawaiian islands are blessed with a pleasant climate, peaceful vistas of mountains and the ocean, exotic birds, trees, and flowers, and the absence of poison ivy, oak and sumac. Mango, however, is abundant and frequently causes dermatitis in people with a history of poison ivy dermatitis. This article will emphasize the cross reactions and the ubiquitous character of mango, poison ivy, and related "Rhus" plants.

Each of the Ubiquitous Urushiols belongs to the Anacardiaceae Family, and each has a similar antigenic substance in its sap or fruit. This antigen, a pentadecylcatechol, is responsible for more cases of allergic contact dermatitis in the United States than all other allergens combined! The ubiquitous nature of this group of plants may best be appreciated by the following composite history.

CASE REPORT OF "MR. KATECHOL"

A 35-year-old traveling salesman noted a pruritic vesicular dermatitis on his hands, forearms, and around his mouth after picking and eating mangoes while vacationing in Hawaii.

His past history is replete with recurrent episodes of dermatitis. As a youngster, living on a farm in Pennsylvania, a severe bullous eruption of the hands developed after milking cows. As a teenager, an eczematous dermatitis developed on his knees, pretibials, dorsa of the feet, and the extensor surfaces of his forearms after "playing in the grass." His playmate also developed a similar pruritic eruption on her buttocks and legs.

Because of his occupation he traveled extensively. Mr. Katechol developed blisters on his hands and feet while playing gold in Georgia and after changing a tire in California. While in San Francisco, he purchased a Mah-Jongg set, and soon found out that he was "allergic" to the case. Our hapless hero recalled other episodes of dermatitis. Several years ago while "on the road" he developed a sharply outlined dermatitis encircling his buttocks. Recently, a small area of "eczema" was noted on the back of his neck after wearing a new shirt for the second time. Hoping to get away from his multiple allergies, he came to Hawaii for a vacation. After sitting at a bar he noted pruritus of the elbows. Finally, several days later, he picked and ate the "king of fruits."

Discussion of Case Report

The troubles of our traveler may seem somewhat bizarre and far removed from the simple case of poison ivy dermatitis. The apparently unrelated episodes of eczematous dermatitis are, of course, all caused by members of the "Ubiquitous Urushiols". The first Rhus rash was an indirect one; sap from poison ivy on the Pennsylvania farm was transferred to the udder of a cow, and then to our subject's hands. The second encounter was more direct -- actual contact of poison ivy while "playing on the grass."

Poison sumac in the woods of a Georgia gold course, and western poison oak on the roadside of a California highway were no diagnostic problems for our traveler. He also realized that there was something on the Mah-Jongg case to which he was allergic -- the lacquer finish. A lacquered bar top was responsible for the pruritus of the elbows. He also discovered that he was sensitive to the "king of fruits" in Hawaii. The eruption on the back of his neck was puzzling, but most perplexing of all was the encircling rash on the buttocks.

A black laundry mark on his shirt collar caused the contact dermatitis on the back of his neck; a lacquer finish of a hotel toilet seat explained his ringed rash.

Mango - " 'Watch!' he said crisply. 'You're about to taste the king of fruits.' He gripped one, took out his knife and gashed a complete circle around the long axis. Then he spun the knife, point-over-end, into the tree and with two hands gripped the halves of the fruit twisting them in opposite directions. The fruit tore apart and for the first time the people in Hawaii tasted "Whip's luscious discovery'." (3)

Thus Whip Hoxworth introduced the mango to Hawaii in James Michener's novel "Hawaii". Fortunately, Whip was not allergic to the "king of fruits".

The mango is green when unripe and turns yellow, orange or red as it ripens. Deposits of a shiny, varnish-like substance may be seen on the rind and stem. Since the fruit itself is generally free from urushiol, people sensitive to mango can eat the fruit if it is peeled by someone else. (4).

Urticaria and shock have, however, been reported (5-7) after eating mango! This fruit is usually eaten raw, but is also stewed, frozen, and made into chutneys. Leaves of the mango have been used in Mexico to clean teeth and harden gums, (8) but mango stomatitis has not been reported.

The appearance of the dermatitis from mango, as with each of the ubiquitous urushiols, will, of course, vary with the nature of contact. Perioral areas and forearms are most commonly involved. Keil (4) states that the absence of linear arrangement of vesicles is rather characteristic of mango dermatitis.

While this is usually true, an interesting exception may be noted. This patient, a dentist, doubting a diagnosis of mango dermatitis of his face, hands, and genitals, scratched his forearm with the stem of a mango to confirm the diagnosis!

Cashew Nut Tree - This tree grows throughout the tropics. Its tiny pink flowers develop a kidney-shaped seed that is edible when roasted. The hulls of the nut contain cardol oil, one of the urushiols. Fortunately, the sensitizing property of cashew nut shell oil is destroyed by heat so that eating he roasted nut rarely causes difficulty. Resins, mucilages, and printer's ink made from the cashew nut shell oil, "swizzle sticks" (drink stirrers), and voodoo dolls made from cashew nuts and wood may cause an urushiol dermatitis (9).

Japanese Lacquer Tree - The lacquer finish of furniture and wooden articles may continue to sensitize people for more than 1,000 years, according to Toyama (2). Mijima studied the yellow oil from the Japanese lacquer tree in 1906 and named it "urushiol". He derived the name from the Japanese name for the sap, kiurushi. The "do-it-yourself" wood worker may develop a dermatitis from the lacquer in his workshop while his wife may note a "rash" from a lacquered bracelet or ornamental box.

Marking Nut Tree of India - Frequently called the "dhobie itch" (dhobie is Hindu for washerman), laundry marking ink dermatitis was usually limited to the back of the neck. Fasal, however, pointed out (10) that in Malaya the "dhobie itch" frequently appeared in persons whose laundry was washed at home and thus was not caused solely by laundry marking ink. This may last the life of the clothing because the black oleoresin is not destroyed by boiling (9).

Rengas Tree - Tengas trees, which grow primarily in Malayan jungles, furnish lumber resembling mahogany (11). Like mahogany, its wood is used for furniture. Unlike mahogany, however, rengas sap cross-reacts with other urushiol plants and trees. If rengas wood furniture is varnished before it is thoroughly dried, the sap may come through the varnish and may plague the owner of the furniture for years. Fasal (10) reported extremely severe and extensive cases of contact dermatitis from rengas.

Ginkgo Tree - These unusual unisexual trees (separate male trees and female trees!) are unlike any other living tree and would be extinct today if not for the care of the Buddhist priests of China and Japan (12). After pollination, pairs of ovules develop into yellow seeds. The outer layer of the seeds break open when they fall to the ground and cause an offensive smell. The central nut is edible when roasted and is a delicacy in the Orient. Sowers (13) reported ginkgo dermatitis in 35 students at a Virginia preparatory school. The students all developed a contact dermatitis on their legs after stepping on the fallen seeds.

Poison Ivy, Oak, and Sumac - Rhus dermatitis from these related "poison plants" is the most common cause of contact dermatitis. The chemistry of poison ivy and the related urushiols has been extensively studied by Dawson (2). The characteristics of the plants are well known to Girl Scouts and campers. Fisher (9) points out that "city folk" often acquire poison ivy dermatitis when visiting cemeteries and may even have poison ivy plants growing as ornamental vines on houses! While direct contact with the leaves is the most frequent means of getting "poisoned", indirect contact is not rare. Uticaria and erythema multiform-like eruptions, as well as fatalities, have been reported from severe sensitivities to these plants.

The interested reader may obtain an illustrated pamphlet on identification, precautions, and eradication of these plants. (14).

References

1. Webster's Seventh New Collegiate Dictionary, G. & C. Merriam Co., Springfield, Mass., 1963.

2. Dawson, C. R.: The Chemistry of Poison Ivy, Trans. N.Y. Acad. Sco., Series II, 18:427, 1956.

3. Michener, J.: Hawaii, pg. 511, Bantam Books Inc., New York, 1961.

4. Keil, H.; Wasserman, D.; and Dawson, C.R.: Mango Dermatitis and Its Relationship to Poison Ivy Hypersensitivity, Ann. All., 4:268, 1946.

5. Lindenbaum, S.: Allergic Reactions to Mangifera indica (Mango), Harefuah, 62:422, 1962.

6. Ruben, J. M. et al: Shock Reaction Following Ingestion of Mango, J.A.M.A., 193:147, 1965.

7. Dang, R. W. M., and Bell, D. B., II: Anaphylactic Reaction to the Ingestion of Mango, Case Report, Hawaii Med. Jour., 27:149, 1967.

8. Hargreaves, D. B.: Tropical Trees, pg. 47, Hargreaves Industrial Publication, Portland, Oregon, 1965.

9. Fisher, A. A.: Contact Dermatitis, pg. 82-90, Lea and Febiger, Philadelphia, 1967.

10. Fasal, P.: Cutaneous Diseases in the Tropics, Arch. Derm. & Syph., 51:163, 1945.

11. Foxworthy, F. W.: Commercial Timber Trees of the Malay Peninsula, pg. 140-144, Fraser and Neave, Ltd., Singapore, 1927.

12. Novac, F. A.: The Pictorial Encyclopedia of Plants and Flowers, pg. 95, Crown Pub. Inc., New York, 1966.

13. Sowers, W. F. et al: Ginkgo-Tree Dermatitis, Arch. Derm., 91:452, 1965.

14. Poison Ivy, Poison Oak and Poison Sumac: Identification, Precautions, Eradications, Bulletin 1972, U.S. Dept. Agriculture, May 1967.