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Diagnosis of exogenous allergic alveolitis
Last reviewed: 06.07.2025
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Clinical examination
Symptoms of exogenous allergic alveolitis do not depend on the type of allergen. In acute onset, flu-like symptoms (chills, fever, headache, myalgia) appear several hours after massive contact with the allergen. Dry cough, shortness of breath, scattered small and medium-sized moist rales appear; there are no signs of obstruction. Asthma-like symptoms are observed in children with atopy. When the allergen is eliminated, the symptoms disappear/subside after several days or weeks.
Laboratory diagnostics
In the hemogram, eosinophilia is not characteristic of this phase of the disease; sometimes slight leukocytosis with neutrophilia is noted.
Instrumental methods
On the chest X-ray, changes in the form of small (miliary) focal shadows are noted, located mainly in the area of the middle sections of the lungs. Sometimes a picture of decreased transparency of the lung tissue is described - the "ground glass" symptom. Multiple infiltrative cloud-like or denser shadows may also be noted, characterized by reverse development over weeks and months. In some cases, no pronounced X-ray changes are observed. Exogenous allergic alveolitis is characterized by the disappearance of X-ray changes after cessation of contact with the allergen (especially against the background of glucocorticoid therapy).
When studying the respiratory function, a decrease in the vital capacity of the lungs is noted (up to 30% of the expected value), sometimes signs of obstruction (decreased patency of small bronchi, hyperinflation of the lungs). These indicators are normalized when contact with the allergen ceases.
Repeated contacts with the allergen provoke relapses of the disease, which are longer and more severe. Often the exacerbation is subacute and remains unrecognized, which leads to the transition of the disease to a chronic form unexpectedly for the patient and the doctor.
Clinical examination
Chronic form of the disease is characterized by constant shortness of breath, cough with mucous sputum. Shortness of breath increases with physical exertion, cyanosis develops. Constant crepitant rales are heard during auscultation. The patient's health gradually worsens, weakness, rapid fatigue, loss of appetite and weight loss, and decreased motor activity appear. Visually, chest deformation is determined in the form of its flattening, changes such as "drumsticks" and "watch glasses" develop.
Laboratory diagnostics
No specific changes are observed in the biochemical blood test. Humoral and cellular immunity indicators are within normal limits. An increase in the level of circulating immune complexes is characteristic.
Instrumental methods
When studying the respiratory function, a restrictive type of ventilation disorders is noted. The vital and total lung capacity indicators are reduced, the lung compliance is reduced, and according to body plethysmography, the specific bronchial conductivity is increased. The diffusion capacity of the lungs is reduced due to thickening of the alveolar-capillary membrane and disturbance of ventilation-perfusion relations. Hypoxemia is expressed with normal values of p a O 2.
Radiographic changes are significant: diffuse enhancement and deformation of the pulmonary pattern due to fibrous thickening of the pulmonary interstitium. Cystic enlightenment may be detected later.
The bronchoscopic picture is unchanged.
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