Respiratory sensitisation

European Centre for Ecotoxicology and Toxicology of Chemicals, Skin and Respiratory Sensitisers Reference Chemical Data Bank, Tech. Rep. No. 77, Brussels, 1999. 

Several instances of respiratory sensitisation resulting from exposure to reactive dyes have been reported. If an individual becomes sensitised to reactive dyes, it is essential that any future contact with these dyes or other respiratory allergens be avoided. Subsequent exposures may cause anaphylactic shock and can progress into convulsions, coma and death. As yet, there is no animal test that can be used to predict reliably the potential of a reactive dye to cause respiratory sensitisation [1]. 

Mutagenicity and carcinogenicity are generally considered to be non-threshold effects, unless a non-genotoxic mechanism can be established with a NOEL (or NOAEL or LOAEL). Risk assessment is based on establishing whether exposure is prevented. A similar process of preventing exposure also applies for skin and respiratory sensitisers, since there is no means of identifying a dose or concentration below which adverse effects will not occur in someone already sensitised to a particular substance. 

Baur, X. 2005. Enzymes as occupational and environmental respiratory sensitisers. Int Arch Occup Environ Health 78(4) 279-286. 

DEARMAN, R.J. BOTHAM, PA. (1990) Inhalation exposure to respiratory sensitising chemicals down-regulates guinea pig IgE and pulmonary responses. International Archives of Allergy and Applied Immunology, 92, 425 -32. 

MORRIS, L. (1994) Respiratory sensitisers. Controlling peak exposures. Toxic Substances Bulletin, 24, 10. 

Pauluhn J. Predictive testing for respiratory sensitisation. Toxicol Lett 1996 86 ... 

If PU resins with such isocyanate impurities are allowed to remain in contact with the skin, they may produce redness, swelling, and blistering of the skin, and respiratory sensitisations (an allergic, asthmatic type reaction) may occur, with rather with low dose tolerances [62]. 

If harmonised classification then normally for all categories of danger If harmonised classification then for substances which are carcinogenic, mutagenic, toxic to reproduction or respiratory sensitisers other effects on a case-by-case basis... 

In the case of the German and UK systems a distinction needs to be drawn between solvents with TRKs or MELs on the one hand, and those with MAKs or OESs on the other. MAKs and OESs are established for those substances for which it is believed that there is a clear threshold of exposure, below which no adverse effect on health is likely to occur. For some substances (e.g. genotoxic carcinogens and respiratory sensitisers), there are theoretical grounds for considering that there is no such threshold. 

Respiratory sensitising/inhalant allergenic causes allergy via inhalation... 

Ebtample of adverse effect Irritant to the skin or eyes Weak (skin or respiratory) sensitisers Sensitisers Severe sensitisers... 

Safety. Most countries have government guidelines on safe handling and use of chemicals, such as UK Health Safety Executive COSHH (control of substances hazardous to health), which is more focused on exposure risk. This can cause problems, such as when HSE issued a chemical alert about glutaraldehyde, and its potential for causing respiratory sensitisation. Immediately, several customers asked to change from glutaraldehyde to a different chemistry. 

Bronchial asthma is defined as breathlessness due to narrowing of the small airways and it is reversible, either spontaneously or as a result of treatment. It may follow inhalation of a respiratory sensitiser or an irritant toxic substance. S5unptoms due to sensitisation may be delayed for weeks, months or even years S5miptoms due to a toxic substance occur within hours of inhalation, resolve spontaneously but can persist indefinitely. The toxic response is called reactive airways dysfuncticm (RAD) syndrome. Most cases of occupational asthma are due to sensitisation and are listed as prescribed diseases for purposes of statutory compensation. The sensitising substances listed are ... 

Respiratory sensitisers may be referred to as asthmagens. In 1989 Surveillance of Work Related Respiratory Disease (SWORD) was started and contains reports by respiratory and occupational physicians. 

The 1993 ACGIH TLV Booklet lists rosin core solder thermal decomposition products as resin acids—colophony as a sensitizer reduce exposure to as low as possible. The recent British Approved Code of Practice, Control of Respiratory Sensitisers, also considers solder flux a respiratory sensitizer (along with spores from moldy hay, isocyanates, flour dust...). ]... 

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