[Delayed asthma on diphenylmethane diisocyanate (MDI). The importance of a professional history. The utility and danger of the inhalation tests. Apropos five cases].

While asthma on toluene diisocyanate (TDI) is well known, asthma on diphenylmethane diisocyanate (MDI) has been less frequently described. Following publication of a case in 1972 another is described which was observed in a similar situation (welding of polyurethane belts) and for which the diagnosis remained obscure for some time. A questionnaire sent to factories using this type of belt revealed two other cases of asthma on MDI. A fifth case is described in which provocative testing induced severe cardiovascular disturbances within a few hours after inhalation. Following a short review of the literature, the four new cases mentioned above are presented together with spirometric studies (provocative testing) and immunological investigations.