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Toxicological information

Sensitisation data (human)

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Administrative data

Endpoint:
sensitisation data (humans)
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Does not include experimental toxicological data

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1999

Materials and methods

Study type:
other: review paper

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Commercial Diisocyanates

Method

Type of population:
other: not applicable
Subjects:
not applicable
Clinical history:
not applicable
Controls:
not applicable
Route of administration:
other: not applicable
Details on study design:
Review of advantages, limitations and validity of various methods and diagnostic Guidelines utilized in the evaluation of diisocyanate asthma.

Results and discussion

Results of examinations:
Recommended methods for evaluation of diisocyanates asthma are similar to approaches for other causative agents. Serologic assays of specific IgE are specific but insensitive diagnostic markers of diisocyanate asthma. If possible, workers should be evaluated, while at work, in order to demonstrate work-related changes in lung function associated with diisocyanate exposures. Specific bronchoprovocation challenge testing with diisocyanates, is reserved for situations where diagnosis cannot be confirmed at work. Such tests can be performed safely but should be conducted exclusively at specialized centers by experienced personnel.

Any other information on results incl. tables

Algorithm for confirming a suspected diagnosis of occupational asthma (Bernstein, 1993, Figure 3)

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 ...................................

Clinical History Positive

Skin test or serum specific IgE (if possible)

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...................................

\/

 ...................................

 ...................................

Methacholine test at work or reversibility in FEV1

 ...................................

 ....................../

.

\.....

Negative

Specific Inhalation Challenge

<-

Positive or

|

/.............. ......................\

|

|

\/

\/

|

|

Positive

Negative

|

|

|

\/

\/

|

|

Workplace challenge or serial PEFR studies

|

|

Positive

Negative

\/

\/........................................\/

\/

No Asthma

Occupational Asthma

Non occupational asthma

( \/ indicates a downwards pointing arrow)

Applicant's summary and conclusion

Conclusions:
Among workers with diisocyanate-induced OA, an earlier diagnosis and a trend to better outcome was found in workers from companies that were identified to be in compliance with surveillance measures (Tarlo 97, Park and Nahm 1997).

Published diagnostic guidelines for occupational asthma are directly applicable to the evaluation of diisocyanate asthma. A clear diagnosis usually requires a combination of investigations (serial peak expiratory flow recordings, methacholine challenges, while the subject is still in the workplace.

Although, specific inhalation challenge (SIC) performed in a hospital laboratory remains the gold standard for the diagnosis of airway changes upon contact with the diisocyanate compound (Pezzini et al. 1984), these challenges can only be performed safely at specialized centers, making them expensive and less accessible. There have been numerous studies that have evaluated associations between DA and elevations in serum specific IgE and IgG antibodies for diisocyanate antigens. Elevated levels of diisocyanate-antigen specific IgE antibody are often predictive of diisocyanate asthma, but these assays do not possess adequate sensitivity for screening exposed worker populations. Serum specific IgG assays for diisocyanate antigens lack both diagnostic sensitivity and specificity.

The paper under review utilize physiciologic studies such as serial measurement of peak expiratory flow rates (PERFs) and non-specific bronchial hyperresponsiveness (NSBH) to provide direction to primary care physicians who are asked to evaluate workers for suspected diisocyanate related occupational asthma. However, this step-wise approach to the diagnosis of diisocyanate asthma (OA) is time consuming and fairly complex. Therefore, a physician should be consulted who is experienced in the evaluation of occupational lung disorders.