Longitudinal Study of Pediatric Urticaria Pigmentosa

Urticaria pigmentosa (UP) is the most common form of mastocytosis in children and is associated with systemic signs, symptoms, and triggers. To our knowledge, the effect of UP on children's quality of life has not been studied. The objective of the current study was to characterize the natural history, triggers, and complications of pediatric UP, identify prognostic indicators, and determine its effect on quality of life.

Between 2002 and 2007, children with three or more mastocytomas diagnosed by a pediatric dermatologist were recruited during visits at the Children's Hospital of Wisconsin Dermatology Clinic (Milwaukee, WI). Research visits were conducted every 3 years and telephone interviews yearly. The Children's Dermatology Life Quality Index was administered to subjects 4 years of age and older at enrollment. Laboratory test results were collected for subjects younger than 4 years at enrollment. Subjects were followed until UP resolution or study end in August 2015.

The final cohort size was 43 subjects followed for a median of 8.1 years. Twenty-six subjects were followed through study completion. At age 12 years, 6 patients had disease resolution and 14 remained active. Patients who had disease resolution before age 12 years were more likely to be male and had fewer years of age and smaller lesions, fewer affected areas, and earlier onset. Common medications and anesthetics resulted in no serious reactions. Hymenoptera stings occurred in 51%, with no reports of anaphylaxis. No patient reported a severe effect on quality of life, with most indicating mild to no effect.

Severe complications are not common with historically identified triggers. Disease does not resolve before adolescence in most children. UP has a minimal effect on quality of life for most children.