11th January 2024

History

Due to the wide variety of aetiologies, a detailed history is the key to establishing ILD diagnosis.

Symptoms

When enquiring about symptoms, particular attention should be paid to their onset (days/weeks/years), timing (time of day/day of the week/seasonal variation) and locations at which they occur (work/home).

Past medical history

• History of chronic illnesses, especially of connective tissue disorders, cardiac disorders or autoimmune conditions, could point towards a cause for ILD – either the disorder itself or medications used to treat it.
• It is also important to ask about any recent acute illnesses, including respiratory and urinary tract infections. Patients might not bring these up, deeming them irrelevant, but ILD can occasionally follow chest infections or be a consequence of an antibiotic treatment. Additionally, frequent infections might suggest immunocompromised state and possible infectious aetiology of ILD.
• Note any atopic history, e.g. asthma and allergic rhinitis, as they suggest eosinophilic pneumonia or Churg-Strauss syndrome.

Drug history

• As discussed above, many medications have been implicated in pulmonary toxicity, so it is important to take full drug history of both current and previous medications. History should include over-the-counter (OTC) drugs, birth control, and any supplements. Always establish a clear timeline of when medications were taken relative to the symptoms.
• Enquire about other treatments, such as radiotherapy.

Family history

• Family history can be useful, as certain ILDs have a clear inheritance pattern, e.g. autosomal dominant in familial pulmonary fibrosis and tuberous sclerosis and autosomal recessive in many metabolic disorders.
• Sarcoidosis seems to occur more in certain families, suggesting a genetic component, although the pattern of inheritance is less clear.

Social history

• Illicit drug use, alcohol and smoking history are all very relevant in ILD history. Both smoking and certain recreational drugs are well-established causes of ILD, while excessive alcohol use might lead to recurrent aspiration or pulmonary hypertension secondary to liver disease.
• Occupational history – lifelong occupational history should be elicited. If exposure to harmful materials (e.g. silica, asbestos) is suspected but not clear from history, a patient should be advised to seek a Safety Data Sheet (SDS) from the employer, which documents hazardous materials at workplace. Remember that a patient might be eligible for compensation if they develop occupation-related pneumoconiosis.
• Environmental exposures – respiratory symptoms with fevers occurring at workplace or during particular activity, and disappearing in other environments, should raise suspicion of HP. Ask about any regular exposure to common triggers such as birds, pets and hot tubs (see Table 1). Note that symptoms might develop secondary to a passive exposure to the causative antigen from another family member, so good exposure history should include that of all close contacts of the patient.