Occupational asthma (OA) with sensitization to diphenylmethane diisocyanate (MDI) presenting at the onset like a reactive airways dysfunction syndrome (RADS)

Authors

  • Luca Perfetti MD,

    Corresponding author
    1. Servizio Autonomo di Allergologia e Immunologia Clinica, Fondazione “S. Maugeri,” Clinica del Lavoro e della Riabilitazione, IRCCS, Istituto Scientifico di Pavia, Italy
    • Servizio di Allergologia e Immunologia Clinica, Fondazione Salvatore Maugeri, IRCCS, via Ferrata 8, 27100 Pavia, Italy.
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  • Barbara Bramé MD,

    1. Servizio Autonomo di Allergologia e Immunologia Clinica, Fondazione “S. Maugeri,” Clinica del Lavoro e della Riabilitazione, IRCCS, Istituto Scientifico di Pavia, Italy
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  • Massimo Ferrari MD,

    1. Scuola di Specializzazione in Medicina del Lavoro II, Sezione di Medicina del Lavoro e Medicina Preventiva dei Lavoratori, Universita' degli Studi di Pavia, Italy
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  • Gianna Moscato MD

    1. Servizio Autonomo di Allergologia e Immunologia Clinica, Fondazione “S. Maugeri,” Clinica del Lavoro e della Riabilitazione, IRCCS, Istituto Scientifico di Pavia, Italy
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Abstract

Background

Two types of OA are distinguished: immunological (OA with sensitization) and non-immunological, i.e., irritant induced asthma or reactive airways dysfunction syndrome (RADS).

Methods

We describe the case of a worker who developed respiratory symptoms after a spill of diphenylmethane diisocyanate (MDI) at the workplace. RADS was initially diagnosed and the worker resumed working. The progressive worsening of symptoms and the appearance of symptoms–work relationship one year later, when concentrations of isocyanates were no longer “irritant,” suggested immunological OA.

Results

The diagnosis was confirmed by specific inhalation challenge test, followed by removal from exposure and complete recovery.

Conclusions

In the case of RADS due to an agent with both irritant and sensitizing properties, history should be repeatedly assessed for a possible symptom–work relationship. If this is found, further investigations should be carried out, including specific inhalation challenges, to confirm the possibility of immunological OA. Am. J. Ind. Med. 44:325–328, 2003. © 2003 Wiley-Liss, Inc.

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