What are the key clinical features to consider when diagnosing occupational asthma in a patient with a history of exposure to respiratory irritants?

When diagnosing occupational asthma in a patient with a history of exposure to respiratory irritants, key clinical features to consider include:

• Adult-onset asthma or reappearance of childhood asthma, especially if poorly controlled or established asthma is present.
• Symptom variation related to work exposure: Symptoms that are worse during workdays and improve on days away from work, during holidays, weekends, or longer breaks.
• Typical asthma symptoms: Wheeze, noisy breathing, cough, breathlessness, or chest tightness, with possible variation such as worsening at night or early morning.
• Triggers that exacerbate symptoms: Exposure to specific occupational respiratory irritants or allergens.
• Absence of alternative diagnoses: Consider and exclude other causes of respiratory symptoms.

Referral to an occupational asthma specialist is recommended for suspected cases to confirm diagnosis and guide management.

Physical examination may reveal expiratory polyphonic wheeze but can be normal even in asthma.

Objective testing is necessary to support the diagnosis alongside clinical history.

Recording detailed symptom patterns in relation to work exposure is essential for diagnosis.

All these points align with the BTS/NICE/SIGN guidelines on asthma diagnosis and occupational asthma assessment.

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