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Epidemiologic Notes and Reports Mucuna pruriens- Associated Pruritus -- New Jersey

On October 6, 1985, a Paterson, New Jersey, Fire Department ambulance responded to a call reporting two people with severe pruritus. On arrival, the two emergency medical technicians (EMTs) found a Spanish-speaking couple living above a beauty salon who described severe itching, which they attributed to "voodoo beans" found in their beds. They displayed several fuzzy bean pods. Soon after their arrival, the EMTs developed pruritus. All four individuals went to an emergency room complaining of itching and skin discomfort. On examination, both members of the couple had erythematous macular rashes on their extremities and bodies; the EMTs had rashes on their arms. There were no respiratory problems. Because of the unknown etiology of the symptoms, two were given epinephrine injections; the others received antihistamines and topical steroid cream. Symptoms resolved within 1-2 hours of treatment. The admitting nurse, who put an arm around one patient, developed a pruritic erythematous area on her inner forearm approximately 20 minutes later. This resolved an hour after washing her skin with soap and water. A policeman who went to the apartment and a worker who collected trash outside the following day also developed itching and received similar emergency-room treatment. Patrons and employees of the shop below and neighbors of the couple had no similar symptoms over the 2-day period.

An industrial hygienist with the local health department went to the site in complete protective gear to look for possible chemical contamination from the beauty salon. Visual inspection and screens for ionizable organic vapors were negative, but he retrieved another bean pod. The botanical samples were sent to Rutgers University, where the plant was identified as Mucuna pruriens. Recommended decontamination procedures for the apartment included steam cleaning of all fabrics and rugs, HEPA Vac cleaning of floors and countertops, and destruction of any fabrics that could not be cleaned. Reported by D Fairbrothers, MD, E Kirby, MD, Rutgers University, New Brunswick, Barnert Memorial Hospital Center, Paterson, RM Lester, PC Wegmann, Paterson Div of Health, F Marshall, WE Parkin, DVM, State Epidemiologist, New Jersey Dept of Health; Div of Field Svcs, Epidemiology Program Office, CDC.

Editorial Note

Editorial Note: Mucuna pruriens, a legume known from Medieval Latin botanical works with the Latin synonym Stizolobium pruriens (1), was first described in the English literature in 1804. The plant is variously called cowitch, cowhage (derived from the Hindu name, "kiwach" or "bad rubbing"), kaunch, and pica-pica (2); the common names are not specific. It grows wild in the tropics, including India, and tropical islands, including the Bahamas (3,4); its range may extend to southern Florida.

Each 10- to 13-cm fruiting pod bears approximately 5,000 barbed, easily detachable spicules measuring 2 mm by 20 um that cause dermatitis through an inflammatory response, presumably an immediate hypersensitivity reaction. Hairs from dried pods, as in herbarium specimens, remain potent (5). The spicules have been sold commercially as itching powder and, at least through 1950, as an oral vermifuge (1,6).

In 1955, studies showed that introduction of one spicule through the epidermis with friction or pressure led to a burning itch lasting up to 30 minutes (1). Spicules could be removed from the skin by washing or by applying an adhesive tape. Mucunain, a protein with endopeptidase and dipeptidase activity, was identified as the active pruritic agent. The protein was extractable only from spicules using aqueous solutions and could be inactivated by autoclaving, changing the pH, or using a similar denaturing process that did not change the spicule structure. Further investigations confirmed the biochemical nature of the pruritic agent, identified as a thermolabile protein of molecular weight 40,000 (7).

Emergency-room personnel should be alert to the possibility that members of some subcultures in this country may be exposed to Mucuna pruriens. Pods and contaminated fabrics should be handled with caution. Symptoms resolve spontaneously within several hours, but antihistaminic therapy appears to be effective for faster resolution.


  1. Shelley WB, Arthur RP. Studies on cowhage (Mucuna pruriens) and its pruritogenic protease, mucunain. AMA Arch Dermatol 1955;72:399.

  2. Bentley R, Trimen H. Medicinal plants. Vol II. London: J. & A. Churchill, 1880.

  3. Britton NL, Millspaugh CF. The Bahama flora. New York, 1920:188-9.

  4. Maheshwari JK. The flora of Delhi. New Delhi: Council of Scientific and Industrial Research, 1963:129.

  5. Lewis WH, Elvin-Lewis MPF . Medical botany. New York: John Wiley & Sons, 1977:78-81.

  6. Fisher AA. Contact dermatitis. 2nd ed. Philadelphia: Lea & Febiger, 1973:248.

  7. Denman ST, Wuepper KD. Histologic and biochemical characteristics of mucuna pruriens. Clin Res 1982;30:581A.

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