Occupational asthma caused by palladium

Occupational exposure to complex platinum salts is a well-known cause of oc cupational asthma, Although there is evidence that platinum refinery worker s may also be sensitized to other precious metals, such as palladium or rho dium, no instances of occupational asthma due to an isolated sensitization to palladium have been reported. A case is reported of occupational rhinoconjunctivitis and asthma in a prev iously healthy worker exposed to the fumes of an electroplating bath contai ning palladium, There was no exposure to platinum. Sensitization to palladium was documented by skin-prick tests, The skin-pri ck test was positive with Pd(NH3)(4)Cl-2, but not with (NH4)(2)PdCl4. Corre sponding salts of platinum were all negative, a bronchial provocation test with Pd(NH3)(4)Cl-2 (0.0001% for a total of 315 s, followed by 0.001% for a total of 210 s) led to an early decrease in forced expiratory volume in on e second (-35%). A similar exposure (0.001% for a total of 16 min) in an un related asthmatic gave no reaction. This case shows that an isolated sensitization to palladium can occur and t hat respiratory exposure to palladium is a novel cause of metal-induced occ upational asthma.