Idiopathic pulmonary hemosiderosis is caused by recurrent diffuse alveolar hemorrhage with permanent consequences. It is one of the types of primary pulmonary hemosiderosis and its diagnosis is based on the classical association of iron deficiency anemia, diffuse pulmonary infiltrates and hemoptysis. The onset of the disease can be at any age and often goes unrecognized in children.
Idiopathic pulmonary hemosiderosis patients present with symptoms associated with pulmonary suffering and signs of anemia, usually before reaching the age of 10 years . Respiratory complaints, often recurrent or chronic, include coughing (dry or productive), wheezing, dyspnea, tachypnea, and hemoptysis, sometimes being wrongly diagnosed with lower respiratory infections . However, hemoptysis is sometimes absent in children due to the fact that they swallow their sputum , but this does not exclude the presence of the disease. Symptoms may occur in an insidious or acute manner and initial presentation may be dramatic, with cyanosis, hypoxemia, respiratory failure, tachycardia, and fever. Clinical diagnosis is difficult in these cases, especially since pulmonary auscultation reveals crackles (caused by fibrosis  ) and pneumonia is easily suspected. Chronic but limited lung bleeding leads to more non-specific findings, like pallor, asthenia, exercise intolerance, failure to thrive, unsatisfactory ponderal and statural curves and finger clubbing.
Idiopathic pulmonary hemosiderosis may be accompanied by other illnesses, such as celiac disease  or von Willebrand disease. These associations induce more severe anemia, as the first one is a bleeding disorder per se, and the second one leads to enteral blood loss. Celiac disease may also cause flatulence, steatorrhea, and diarrhea, but the presence of these findings is not compulsory. Other associations include chronic granulomatous disease , idiopathic  and rheumatoid arthritis .
Idiopathic pulmonary hemosiderosis is a diagnosis of exclusion. Therefore cow milk protein allergy and autoimmune diseases, as well as other frequently associated illnesses like systemic lupus erythematosus, celiac disease, Goodpasture syndrome or Wegener granulomatosis must be ruled out. Towards this purpose, the physician may find it useful to order serum precipitins to casein and lactalbumin titers, anti-glomerular basal membrane, antinuclear antibodies, anti-DNA, anti-gliadin, anti-reticulin and anti-endomysial antibodies. The complete cell blood count will reveal the presence of anemia and possible eosinophilia. The anemia has iron deficiency characteristics (hypochromic and microcytic) . Enteral blood loss is detected using guaiac tests. Keeping in mind that sputum is often swallowed by children, a gastric lavage analysis and bronchoalveolar lavage may prove useful, as they demonstrate the presence of presence of hemosiderin-bearing macrophages . Despite the fact that pulmonary biopsy remains the gold standard for diagnosis , it can also be achieved using bronchoalveolar lavage  . If sputum can be obtained, a cytological and bacteriologic analysis is necessary. Urinalysis may reveal proteinuria or hematuria. Coagulation disorders should also be investigated.
Chest radiography reveals bilateral alveolar infiltrates which are seen as opacities located in the basal and perihilar areas, that may be accompanied by edema . After blood absorption, during remission phase, a reticular pattern remains.  Hilar adenopathy may be present in the acute phase. A more accurate diagnosis may be obtained with computed tomography, that also characterizes bronchial and vascular status, but pulmonary embolism is best excluded by ventilation/perfusion nuclear scanning.