Unusual presentation of maculopapular cutaneous mastocytosis in an infant with skin of color

Maculopapular cutaneous mastocytosis is caused by an increase in mast cells in cutaneous tissues and extracutaneous organs in both pediatric and adult populations. Pediatric-onset mastocytosis is typically diagnosed before age two, presenting with urticaria pigmentosa.1 Typical characteristics include multiple reddish brown lesions in the form of macules, plaques, or nodules ranging in size from a few millimeters to 1 to 2 cm.1 Formation of wheals or vesicles after rubbing a cutaneous mastocytosis lesion, known as the Darier sign, is commonly seen and is used in diagnostic evaluation.