Mimicking hypersensitivity pneumonitis as an uncommon initial presentation of chronic granulomatous disease in children.

Dry cough, dyspenea and diffuse centrilobular nodules in both lungs of radiologic findings similar to hypersensitivity pneumonitis (HP) are rare initial presentation in chronic granulomatous disease (CGD). CGD is remarkable for increased susceptibility to bacterial and fungal infections as well as high sensitivity to inciting antigens such as Aspergillus species due to dysregulated inflammation. We identified three children who had an initial presentation mimicking HP and were subsequently diagnosed as CGD. All patients developed invasive pulmonary A. fumigatus infection (IPAI) following systemic glucocorticoid therapy. Two of the three patients were found to have mutations in NCF1 gene and one patient in NCF2 gene. As HP is uncommon in children, we should consider the possibility of CGD in children with HP, even in mimicking HP patients with suggestive inhalation history and negative fungal cultures. A prompt diagnosis of CGD is essential to enable initiation of prophylactic antibacterial and antifungal therapies.