Continuous glucose monitoring systems give contact dermatitis in children and adults despite efforts of providing less 'allergy- prone' devices: investigation and advice hampered by insufficient material for optimized patch test investigations.

The following case reports bring in focus the fact that patients sensitized through use of one medical device and being advised the use of another, or find another product for a while useful, are not by necessity free from future episodes of allergic contact dermatitis. The case reports emphasize the need for collaboration since it is impossible for even well-equipped laboratories to properly investigate the medical devices when information on the substances used in production is not uniform and complete and material to investigate are scarce. The importance of adequate patch test series and testing with own material and furthermore the importance to re-analyse medical devices and re-analyse test data are emphasized.