Omenn syndrome: a rare case of neonatal erythroderma

Omenn syndrome is a severe combined immunodeficiency characterized by erythroderma, hepatosplenomegaly, lymphadenopathy and failure to thrive, with activated oligoclonal T lymphocytes and an absence of circulating B cells.A 3 day-old boy presented with a congenital erythroderma. Investigations revealed a marked neutropenia and lymphopenia and the absence of a thymus. Genetic studies showed RAG 1 mutations. He was successfully treated with an HLA identical bone marrow transplantation. Omenn syndrome is a rare severe combined immunodeficiency. Most cases are due to mutations in the RAG genes with autosomal recessive transmission. Our observation is original because of an incomplete clinical presentation. During the course of the disease, the child had no failure to thrive, no organomegaly and no recurrent infection. Immunodeficiency must be excluded in every case of neonatal erythroderma and an immunological assessment should be performed without delay.