Contact Dermatitis, 2001, 44, 246–263 Copyright C Munksgaard 2001 Printed in Denmark . All rights reserved ISSN 0105-1873 Short Communications Occupational allergic contact dermatitis from methylchloroiso methylisothiazolinone (MCI/MI) in a silicone-emulsion lock M. C. C, B. K, M. B, J. B. O’D  M. H. B Contact Dermatitis Investigation Unit, Dermatology Centre, University of Manchester School of Medicine, Hope Hospital, Salford, Manchester M6 8HD, UK Key words: occupational allergic contact dermatitis; silicone emulsion; methylchloroisothiazolinone and methy azolinone(MCI/MI); antimicrobials; preservatives; biocides;lock lubricant;hand cleanser; skin-careproducts. C Munksgaard, 2001. Case Report A 39-year-old man presented with a 2-year history of dorsalhand eczema favouring the finger webs. He had been a vehicle locksmith and electrician for 3 years, han- dling spray-can lock lubricants and washing with indus- trial hand cleansers. Patch testing was positive (ππ) to formaldehyde 1% aq., melamine-formaldehyde resin 10% pet., 2-bromo-2- nitropropane-1,3-diol 0.5% pet. and methylchloroisothi- azolinone and methylisothiazolinone (MCI/MI) 0.01% aq. at both D2 and D3. On enquiry from the manufacturers, the lock lubri- cant was a non-ionic o/w emulsion of a linear polydime- thylsiloxane polymer. We were told that MCI/MI was present, but in too low a concentration to be mentioned on the materialsafety data sheet. The patient’s hand cleanser was also found to have contained MCI/MI up until October 1998. The patient’s hand eczema has im- proved significantly since he stopped using both the lock lubricant and the hand cleanser. Discussion Skin sensitization to biocides is well-documented (1, 2). MCI/MI has caused contact allergy in metalworkers (3) and in the manufacture of binders for paints and glues(4). MCI/MI also sensitizes in cosmetics(5).It does not appear to have been reported before in a lock lubricant. References 1. Cronin E. Contactdermatitis. London: ChurchillLiving- stone, 1980: 664–713. 2. Rietschel R L, Fowler J F. Fisher’s Textbook of contact der- matitis, 4th edition. Baltimore: Williams and Wilkins, 1995: 257–329. 3. NethercottJ R, Rothman N, HolnessD L, O’Toole T. Health problems in metal workers exposed to a coolant oil containing Kathon 886 MW. American Journal of Contact Dermatitis 1990: 1: 94–99. 4. GruvbergerB, Bruze M, Almgren G. Occupational dermatoses in a plant producing binders for paints and glues. Contact Dermatitis 1998: 38: 71–77. 5. DeGroot A C, Herxheimer A.Isothiazoline preservative: cause of a continuing epidemic of cosmetic dermatitis. Lan- cet 1989: 1: 314–316.