Introduction Exposure to chemicals occurs in a wide range of professional fields. Chemicals typically induce delayed, cell-mediated sensitisation, but some chemical agents are able to induce immediate-type allergy. The mechanisms of immediate sensitisation to chemicals are still mainly unknown, but specific IgE seems to play a role, at least for some chemical groups. The aim of our study was to evaluate the diagnostic procedures of occupational immediate allergic diseases caused by chemicals and assess the feasibility of skin testing in the diagnostics.

Methods We retrospectively reviewed the patient files of the Finnish Institute of Occupational Health for the period of 1991–2011 to find patients diagnosed with immediate sensitisation to chemicals. We collected data on occupation, exposure, work-related symptoms, clinical and immunological test results, and occupational allergic diseases.

Results Positive skin prick tests (SPT) were noted for organic acid anhydrides, diisocyanates, persulfates, epoxy resin, chlorhexidine and aziridine. Amine hardeners and formaldehyde induced multiple small indifferent reactions. For several other groups of chemicals sporadic or no positive SPTs were noted. Occupational contact urticaria (CU) caused by chemicals was diagnosed in 41 patients during the study period, 21 of them caused by acid anhydrides. More than half of the CU patients (54%) had a concomitant allergic airway disease.

Discussion SPTs provide a fast and safe complementary tool for diagnosing immediate allergic diseases to some chemical groups, but the results should be interpreted cautiously and related to symptoms and other clinical tests. Occupational CU caused by chemicals is often accompanied by occupational airway diseases caused by the same agent.