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Phytophotodermatitis among Grocery Workers -- Ohio

On July 5, 1984, a 33-year-old woman presented to an Ohio medical clinic with a bullous, erythematous, nonpruritic, discrete rash of the left forearm of 6 days' duration. An occupational history indicated that she was a cashier at a supermarket. Several co-workers were reported to have had similar rashes that were attributed to handling celery.

The physician alerted the National Institute for Occupational Safety and Health (NIOSH), and a NIOSH medical officer visited the market. A cross-sectional study of all employees was undertaken. Fifty-two (95%) of 55 current full- and part-time employees were interviewed and examined between July and September. Fourteen (27%) of these workers had papular, well-circumscribed rashes confined to the upper extremities, with residual blistering or hyperpigmentation. Dates of rash onset ranged from April through August, with a peak in July. All cases occurred among cashiers, baggers, and produce clerks (Table 1). None occurred among shelf stockers, delicatessen clerks, meat clerks, or managers.

Cases were significantly more likely than noncases to have had contact with fresh vegetables (100%, compared with 39%; p = 0.009) and with fresh flowers (92%, compared with 29%; p = 0.009). Also, cases were signficantly more likely than noncases to have used a tanning salon during the outbreak period (36%, compared with 5%; p = 0.01). There was suggestive evidence of a multiplicative interaction between produce exposure and use of a tanning salon in the etiology of cases (Figure 1).

On the basis of history and physical examination, a diagnosis of phytophotodermatitis was made in this outbreak. NIOSH recommended that employees handling produce wash exposed areas of hands, wrists, and forearms regularly and avoid either tanning salons or excessive exposure to sunlight. No new cases occurred after October, which is typical for the seasonal pattern of occurrence of this disease. Reported by Div of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, CDC.

Editorial Note

Editorial Note: Skin disorders appear to represent a widespread but largely unrecognized problem among supermarket employees. Many of the rashes among these workers appear to be phytophotodermatitis, a well-circumscribed rash evoked by contact with linear furanocoumarins (psoralens), followed by exposure of the skin to long-wave ultraviolet light (350 nm). It is associated with exposure to a wide variety of fruits, flowers, and vegetables, including celery, dill, parsley, oil from lime peels, parsnip, oil of Bergamont, and chrysanthemums. Exposure to sunlight is sufficient to provoke phytophotodermatitis following contact with psoralens. However, the use of artificial ultraviolet light in tanning salons appears in the present instance to have enhanced this effect.

In phytophotodermatitis, the reaction is typically confined to the initial site of contact and is characterized by redness and blistering in the absence of itching and by residual hyperpigmentation (1). This type of reaction differs from an allergic contact dermatitis in that it requires exposure to ultraviolet light and does not require a period of sensitization. In addition, an allergic dermatitis is usually pruritic.

This outbreak resembles a series of episodes investigated by NIOSH in supermarkets throughout the midwest in 1980-1981. In those episodes, baggers had the highest attack rates of dermatitis (51%). Frequent contact with unpackaged celery and exposure to sunlight during the work-shift were significantly associated with cases (2). Also, an investigation of agricultural field workers in Michigan in 1961 found that celery infected with pink rot (Sclerotinia sclerotiorum) was associated with an outbreak of photodermatitis (3).

It is not possible at present to ascribe the etiology of this outbreak to any single foodstuff. However, since only workers who had contact with fresh produce developed rash, it appears likely that the psoralen-containing agent in the present outbreak is to be found among the vegetables, fruits, or flowers handled in this market. Surveillance of skin rashes in supermarket workers and investigation of additional outbreaks may help to identify a specific etiologic agent.


  1. Mitchell J, Rook A. Botanical dermatology: plants and photodermatitis injurious to the skin. Vancouver, British Columbia, Canada:Greenglass Ltd., 1979:41.

  2. National Institute for Occupational Safety and Health. Health hazard evaluation determinination report no. HE 80-225, Cincinnati, Ohio: National Institute for Occupational Safety and Health, June 1982.

  3. Birmingham DJ, Key MM, Tubich, GE, Perone, VB. Phototoxic bullae among celery harvesters. Arch Dermatol 1961;83:127-41.

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