Pediatric emergency medicine trisk 1814 1814

FIGURE 88.9 Urticaria pigmentosa with Darier sign.

Mastocytoma, Urticaria Pigmentosa
These are red/brown papules that urticate. For additional information please see
Chapter 69 Rash: Neonatal .
Juvenile Xanthogranulomas
Juvenile xanthogranuloma. JXGs can be confused with urticaria pigmentosa or
xanthomas. Numerous yellow or reddish-brown papules appear on the face and
upper trunk in the first year of life. The number of lesions may increase until the
child is 18 months to 2 years of age. Serum lipid levels are normal, and the Darier
sign (urtication after scratching) is negative. The lesions often disappear
spontaneously after 2 years of age; therefore, intervention is generally
unnecessary. When JXGs are multiple, particularly on the head and neck,
evaluation of the eyes for intraocular JXGs is recommended because of their
potential for visual impairment. The presence of JXGs in a young child with
neurofibromatosis (type 1) has been a marker associated with an increased risk of
juvenile myelomonocytic leukemia.