Differential Diagnosis for Dark Blue Area on the Back of a Three Week Old African-American
- Single Most Likely Diagnosis
- Mongolian spot: a benign congenital melanocytic lesion common in African-American, Asian, and Native American infants, typically appearing as a blue or blue-gray macule on the back or buttocks.
- Other Likely Diagnoses
- Bruise or ecchymosis: a common injury in infants, especially if they have undergone a traumatic birth or have been handled roughly.
- Congenital melanocytic nevus: a type of birthmark that can appear as a blue or black lesion, although these are typically more raised and hairy.
- Do Not Miss Diagnoses
- Meningococcemia: a life-threatening infection that can cause purpura or blue-gray lesions, although this would typically be accompanied by other symptoms such as fever, lethargy, and poor feeding.
- Child abuse: although less likely, it is essential to consider non-accidental trauma, especially if the lesion is inconsistent with the provided history or if there are other suspicious injuries.
- Rare Diagnoses
- Blue rubber bleb nevus syndrome: a rare condition characterized by multiple blue lesions, typically on the skin and mucous membranes, which can be associated with gastrointestinal and other systemic manifestations.
- Phakomatosis pigmentovascularis: a rare condition characterized by the combination of a congenital melanocytic nevus and a vascular malformation, which can appear as a blue or purple lesion.