Milk tester's dermatitis

Hand dermatitis is a frequent problem among workers in milk testing laboratories. An epidemiologic study was conducted at the Pennsylvania Dairy Herd Improvement Association Milk Testing Laboratory, where more than 300,000 milk samples are examined monthly for protein, butterfat, and "somatic" cells. These samples are preserved with potassium dichromate for transport from the farm to the laboratory. A survey of the laboratory was conducted and workers were interviewed. Eight of 16 subjects reported a history of occupationally exacerbated hand dermatitis. Three of 16 subjects had positive patch test results to potassium dichromate. Two of 15 subjects who underwent patch testing to milk preserved with potassium dichromate had positive reactions. None reacted to milk alone, bronopol, or Kathon CG. Two workers are receiving workers' compensation because of severe allergic contact dermatitis of the hands to potassium dichromate. We conclude that milk testing laboratory workers are at substantial risk for acquiring allergic contact dermatitis from milk preserved with potassium dichromate.