Isocyanates allergy
A leading cause of occupational asthma, from paints and foams.
About isocyanates allergy
Isocyanates are highly reactive chemicals used to make polyurethane products, including two-pack spray paints, foams, adhesives, coatings and varnishes. They are among the most important causes of occupational asthma in the UK. Unlike protein allergens, isocyanates are low-molecular-weight chemicals, and although they clearly cause airway sensitisation the exact immune mechanism is not fully understood and is not always straightforwardly IgE-mediated. Vehicle sprayers and body-shop workers are a particularly high-risk group, along with those making or applying foams, coatings and adhesives.
Sensitisation can develop after months or years of exposure, sometimes following an accidental high-level release. Once someone is sensitised, even very low concentrations can provoke symptoms within minutes to hours, including cough, chest tightness, wheeze, breathlessness, and a runny or blocked nose and irritated eyes. A characteristic feature is that symptoms often improve on evenings, weekends and holidays and return at work, though reactions can also come on hours later, for example at night after a working day.
Diagnosis is usually coordinated through occupational health using lung-function measurements taken at and away from work, and sometimes specialist tests. The priority is strict exposure control: enclosed processes, spray booths, effective ventilation, correct air-fed respiratory protection and health surveillance. Confirmed occupational asthma is reportable under RIDDOR. Because continued exposure after sensitisation can cause severe and lasting lung damage, prompt recognition and removal from further exposure are essential.
Common triggers
- Isocyanates and products containing it
Symptoms
- Skin rash or dermatitis on exposed areas
- Sneezing, runny nose or watery eyes
- Coughing, wheezing or chest tightness
- Occupational asthma over time
Avoidance & management
- Use recommended protective equipment and ventilation
- Follow workplace exposure controls
- Wash exposed skin promptly
- Report symptoms to occupational health
- Discuss adjustments or alternatives with your employer
Sources & references
Allergy safety: what everyone should know
Mild-to-moderate reaction signs
- Itching, hives or a raised rash
- Swelling of lips, face or eyes
- Tingling mouth, sneezing, runny nose
- Stomach pain, nausea or vomiting
Anaphylaxis — call 999 (UK) or 112 (EU) immediately
- Difficult or noisy breathing, wheeze, persistent cough
- Swelling of the tongue or tightness in the throat
- Dizziness, collapse, pale and floppy (young children)
- Use an adrenaline auto-injector (e.g. EpiPen) at once if prescribed, then call an ambulance even if symptoms improve
Allergy or intolerance? A true allergy involves the immune system and can escalate quickly; an intolerance (e.g. lactose intolerance) is unpleasant but not life-threatening. The symptoms overlap, so self-diagnosis is unreliable.
Getting tested: home-testing kits based on IgG are not diagnostically valid. If you suspect an allergy, ask a GP for referral to an allergy clinic for skin-prick or specific-IgE testing and a supervised food challenge where appropriate.