Metal allergy in cashiers. An in vitro and in vivo study for the presence of metal allergy.

Thirty healthy cashiers continuously exposed to nickel in coins were tested in vivo and in vitro for the presence of metal contact allergy. A traditional epicutaneous test and lymphocyte transformation test were used. We tested for nickel, cobalt and chromium sensitivity. Seven of the 30 cashiers were patch test positive and 3 were in vitro positive to nickel sulphate. Two were in vivo positive to cobalt and only one in vitro positive. None was chromium allergic. There was no correlation between the exposure time and the lymphocyte response towards nickel. The presence of pierced and non-pierced ear lobes was noted with and without eczema in conjunction with the wearing of ear-rings containing nickel. The lymphocyte reactivity showed no significant difference between these groups. Only 5 out of the 12 with ear lobe dermatitis were patch test positive towards nickel. The data suggest that nickel as test substance or released from nickel-containing jewellery can evoke a cutaneous response which is not always associated with allergy.