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Extrinsic Allergic Alveolitis H008

Last amended 
30 June 2015
Current RMA Instruments:
Reasonable Hypothesis SOP
87 of 2011
Balance of Probabilities SOP
88 of 2011
Changes from Previous Instruments:

SOP Bulletin 152

ICD Coding:
  • ICD-9-CM Codes: 495
  • ICD-10-AM Codes: J67
Is specific diagnostic evidence required to apply the SOP? – Yes.

This diagnosis needs to be made by a specialist respiratory or general physician.  To apply the SOP you will also need to identify the specific antigen or antigenic source that has caused the disease in the particular case you are dealing with.  This will be an antigen or antigenic source to which the person has had recurrent exposure (by inhalation), that has been prolonged, heavy or frequent, at the time of the clinical onset of the disease.

Are there sub-factors that require specific information? – No.
Additional diagnoses covered by SOP
  • hypersensitivity pneumonitis due to an inhaled substance (see below);
  • bird-fancier’s lung; farmer’s lung; ventilation pneumonitis; woodworker’s lung;
  • a range of other named types of EAA.
Conditions not covered by SOP
  • hypersensitivity pneumonitis due to ingested drugs or any non-inhaled substance, ICD code 508.8
  • asthma, ICD code 493.9
  • asbestosis, ICD code 501
  • fibrosing alveolitis, ICD code 516.3
  • pulmonary fibrosis, non-specific, ICD code 515
Unconfirmed diagnosis

If, after applying the above information, you are unable to confirm the diagnosis, you should then:

  1. seek medical officer advice about further investigation, or;
  2. generate a diagnostic report, or;
  3. re-encode the condition, if appropriate.

The following may be useful in establishing the diagnosis.

  • A report from a specialist respiratory or general physician, identifying the responsible antigen.

Note: No single test or finding is diagnostic.  A combination of (i) a history, physical findings, pulmonary function tests and chest X-ray consistent with the disease; (ii) repeated heavy or prolonged exposure to a recognised antigen; and (iii) finding an antibody to that antigen, is generally required to make the diagnosis.  An open lung biopsy may be necessary in some cases.  The disease, when chronic, may be difficult to distinguish from other interstitial lung disorders.