[Necrotizing pneumonia in a patient with selective IgA deficiency].

Background: Inborn errors of immunity originate from monogenic mutations that should be considered in the suggestive diagnosis of patients with recurrent or severe infections, allergies, autoimmunity, autoinflammatory diseases, bone marrow failure and malignancy.

Case Report: Pediatric patient, male, 4 years old, treated in the medical service for fever of 39°C, difficult to control. The simple chest x-ray reported left pulmonary consolidation. The infectious condition evolved into necrotizing pneumonia of the left upper lobe, so it was decided to perform a lobectomy. The diagnosis of some inborn error of immunity was suspected. The determination of serum immunoglobulins reported IgA below the reference values. At 4 years he continued to have decreased serum IgA (5.5 mg/dL).

Conclusions: The diagnosis of selective IgA deficiency is established after 4 years of life; However, due to the patient's severe infection, addressing some inborn error of immunity had to be implemented.