What is Blueberry muffin baby?

Blueberry muffin baby, also known as extramedullary hematopoiesis, describes a newborn baby with multiple purpura, associated with several non-cancerous and cancerous conditions in which extra blood is produced in the skin. The bumps range from 1-7mm, do not blanche and have a tendency to occur on the head, neck and trunk. They often fade by 3 to 6 weeks after birth, leaving brownish marks. When due to a cancer, the bumps tend to be fewer, firmer and larger.

It can occur following infection of an unborn baby with rubella, cytomegalovirus, toxoplasmosis, or coxsackie virus. Other viral causes include parvovirus B19 and herpes simplex. Non-infectious causes include haemolytic disease of the newborn, hereditary spherocytosis, twin-to-twin transfusion syndrome and recombinant erythropoietin administration. Some types of cancers can cause it such as rhabdomyosarcoma, extrosseal Ewing sarcoma, Langerhans cell histiocytosis, congenital leukaemia and neuroblastoma. During normal development of an unborn baby, blood production can occur in the skin until the fifth month of pregnancy. Blueberry muffin lesions in the newborn indicate the prolongation of skin blood production after birth.

Diagnosis involves a combination of appearance and laboratory studies, including blood tests for complete blood count, TORCH infections, haemoglobin, viral cultures and Coombs test. A skin biopsy may be useful. Conditions that may appear similar include hemangiopericytoma, blue rubber bleb nevus, hemangioma and glomangioma.

Prognosis is variable based upon the cause of the characteristic rash. Treatment may include supportive care, anti-viral medication, transfusion, or chemotherapy depending on the underlying cause.