Early symptoms of runny rash are mild with no fever or only a slight fever, fatigue, loss of appetite, weight loss, night sweats, and a mild dry cough; severe cases may have high fever, episodes of paroxysmal cough, which may be accompanied by mucous sputum, even hemoptysis, and dyspnea. The lungs may have rales or wet rales on auscultation and sometimes turbid sounds on percussion. The liver is often enlarged in younger children. The duration of the disease is mostly limited to 1 month. The clinical classification is acute and chronic, depending on the intensity and frequency of exposure to antigens. The performance is similar to that of acute bacterial and viral pneumonia. The sensitized person suddenly starts to have a dry cough, fever, chills, general discomfort, and marked respiratory distress after 4 to 8 h of exposure to the antigen. This improvement is often mistaken for the effect of antibiotics, but is most likely a natural consequence of avoiding antigens. Because the diagnosis is unknown, the patient returns to the same place after discharge and the symptoms will flare up again, and this repeated exposure finally leads to irreversible lung tissue damage. X-rays of the chest in the acute phase show tiny nodular infiltrates in the interstitium and alveoli, mostly patchy or diffusely distributed. The nodules range from one to several millimeters in diameter, and alveolar shadows may be seen. Occasionally, during an acute attack, the lungs may be completely normal, especially in the early post-exposure period. Chronic allergic pneumonia results from prolonged exposure to a less concentrated antigen or repeated acute attacks. 50% of cases progress insidiously until pulmonary fibrosis, typically with progressively worse dry cough, dyspnea, anorexia and fatigue, and is often noticed when the lungs have become extensively fibrotic with pulmonary insufficiency, when chronic respiratory failure and congestive right heart failure may be present. It is difficult to distinguish from primary pulmonary fibrosis. Chest X-ray shows extensive interstitial fibrosis with thickened bronchovascular images (texture). The eosinophils in the peripheral blood are larger than normal and contain large granules, and the cell count is increased, accounting for 20% to 70% of the total white blood cells. Immunological examination of the blood may be positive for parasite antibodies; IgE may be as high as 2300 ng/ml, and those with hepatomegaly often show hyperglobulinemia. Parasite egg examination of alveolar lavage fluid and 24h sputum for parasite eggs may be positive. Skin test examination of parasite skin test solution may be positive. Chest X-ray shows cloudy flocculent patches, which may be large or small in extent, and the shadows may disappear within a short period of time and reappear soon after, and the location may be migratory and not constant. Sometimes it can show pulmonary atelectasis. Pulmonary function tests: The disease is mainly characterized by restrictive pulmonary dysfunction, with a marked decrease in lung volume in the acute phase, but little change in spirometry. there is a decrease in FVC, a mild decrease in FEV1, a decrease in pulmonary compliance due to interstitial inflammation, and a decrease in diffusing capacity and arterial partial pressure of oxygen in the lungs due to marked ventilation flow abnormalities. As with the clinical and radiographic changes, the abnormalities of pulmonary function in the acute phase are reversible. In the chronic phase of extensive pulmonary fibrosis, restrictive and obstructive pulmonary dysfunction becomes irreversible. The diagnosis is made based on the clinical presentation of respiratory symptoms including cough, shortness of breath, and fever, as well as the presence of temporary infiltrative shadows on X-ray chest radiographs and eosinophilia in the peripheral blood. The medical history should include a detailed history of medications, food history and other allergies. The diagnosis of the disease is supported by an absolute value of eosinophils in the peripheral blood of more than 3.0×109/L. High levels of blood IgE should be measured. If the disease is suspected to be caused by internal migration of canine and feline roundworms, an enzyme-linked immunosorbent assay (ELISA) can be performed to measure antibodies against canine and feline roundworms to differentiate the disease from infection with human roundworms. The eggs in the stool can only be seen a few days to weeks after the onset of lung lesions, so repeated stool examinations are needed early in the disease and 2 to 4 weeks after the disease to clarify the etiology.