Mongolian spots in newborns are best described as which?

• A. Bluish discoloration of the skin on the back or buttocks that usually fades by 1-2 years and is normal
• B. Bruises from birth trauma
• C. Port-wine stain on the face
• D. Red, scaly rash on the scalp

Answer: (A)

Mongolian spots are benign congenital dermal melanocytosis. They appear as slate-blue patches that are usually located on the lower back or buttocks at birth. The blue color comes from pigment that’s deeper in the skin, so it looks blue rather than brown. These patches typically fade spontaneously by about 1–2 years of age as the pigment lightens, and no treatment is needed. This description—bluish discoloration on the back or buttocks that usually fades by 1-2 years and is normal—fits Mongolian spots best.

Other options describe conditions that are not this benign dermal pigment pattern: birth trauma bruises would not be a common, flat, slate-blue patch that fades; a port-wine stain is a persistent red-to-purple vascular lesion that does not fade; a red, scaly scalp rash sounds like cradle cap or seborrheic dermatitis, not a stable blue patch.