Blueberry muffin baby
Summary
Generalised blue–purple, non-blanching papules/nodules in a neonate due to dermal extramedullary haematopoiesis (or less commonly, skin metastases).
In rad exams it’s a clinical clue to underlying systemic disease that must be further investigated with imaging.
Main aetiologic groups
1. Congenital infections (TORCH & friends)
Mechanism: marrow suppression / haemolysis → extramedullary haematopoiesis
- Classically: congenital rubella.
- Also: CMV, toxoplasmosis, parvovirus B19, syphilis, others.
2. Haematologic / malignant
Mechanism: extensive bone marrow infiltration/replacement → extramedullary haematopoiesis ± direct skin infiltration
- Congenital leukaemia (esp. myelomonocytic).
- Langerhans cell histiocytosis (disseminated / Letterer–Siwe type).
- Occasionally other small round blue cell tumours, e.g. neuroblastoma with skin metastases.
3. Severe haemolytic / hypoxic states
Mechanism: severe chronic anaemia/hypoxia → marked extramedullary haematopoiesis (liver, spleen, skin).
- Haemolytic disease of the newborn (Rh/ABO).
- Twin–twin transfusion
- Severe intrauterine hypoxia, e.g. massive feto-maternal haemorrhage.
