Allergies:

There are a great many professional allergens since there are hundreds of molecules listed as professional allergens.
 
For the immediate allergies, the most frequently mentioned ones are:

• Meals
• Isocyanates
• Squama and animal dejections
• Saw dust
• Dust from grains
• Metals
• Latex

The professional allergens may be classified in 2 categories:

They include metals, chemical substances (isocyanates, sulphites, persulphates…) and more globally non-protein molecules and haptens.
 
Most often, a non IgE-dependent mediated reaction is provoked.  However, certain low molecular weight allergens may be the cause of IgE-dependent hypersensitivity (platinum salts, isocyanates…). Skin tests or specific IgE may then turn out to be positive.  As opposed to high molecular weight allergens, atopy is not a factor that predisposes to sensitivity to low molecular weight allergens.
 
The diseases induced by professional allergens are most often:

• skin diseases ( eczema,  atopic dermatitis)
• respiratory diseases 

Molecules in the professional environment may also trigger delayed cell hypersensitivity, thereby professional contact eczema.  The most often incriminated molecules are:

• Metals:  nickel in metal instruments, chrome in metal instruments but also the tanning of leather, cement, cobalt found in certain cements and paints.
• Hair products:  metals in instruments, paraphenylenediamine in dyes, ammonium persulphate in hair dyes, monothioglycolate in products for permanents, …
• Hospital disinfectants  or ingredients in industrial cleaning products such as quaternary ammoniums, glutaraldehyde, formol, …
• Paints, glues and resins  often sensitised by the preservatives that they contain but especially by resin monomers such as Epoxy or acrylates.
• Plants and flowers
• Drugs handled in a hospital or in the drug industry.
• The components in protective clothing:  agents in the rubber vulcanising of gloves, boots and rubber glasses, chrome in the leather of safety boots.