High prevalence of autoimmune urticaria in children with chronic urticaria.
BACKGROUND
The etiology of chronic urticaria (CU) in childhood often remains unrecognized. Recently, in adults it has been shown that approximately 40% of patients with CU have autoimmune urticaria (AU); however, no data are available in children.


OBJECTIVE
To determine the prevalence and possible risk factors for AU in children with CU.


METHODS
Ninety-three consecutive children (52 male; median age, 7.8 years) with CU were evaluated for AU by means of autologous serum skin test (ASST) in all and serum-induced basophil histamine release (HR-urticaria test) in 52. All other known causes of CU were excluded as appropriate.


RESULTS
A cause for CU was identified in 44 children (47%), whereas 49 (53%) remained idiopathic. ASST and HR-urticaria test had positive results in 22 of 49 (45%) and in 16 of 31 (52%) children with idiopathic CU compared with 1 of 44 (2%) and 5 of 21 (24%) with CU of a known cause, respectively ( P <.00001; P=.09). Sensitivity, specificity, and positive and negative predictive values of the ASST for diagnosing AU are 78%, 85%, 74%, and 88%. The prevalence of AU in childhood is 31% (15/52; 95% CI, 24%-51%). None of the variables studied were predictive for development of AU.


CONCLUSIONS
Our results demonstrate for the first time that children have the same ability as adults to produce functionally active autoantibodies directed against IgE or IgE receptor and that AU occurs in children in as many as 30% of cases. The addition of screening for AU dramatically decreases the rate of the idiopathic form from 52% to 20%.
Brunetti
Luigia
L
Department of Biomedicina dell'Età Evolutiva, University of Bari, Italy. l.brunetti@pediatria3.uniba.it
Francavilla
Ruggiero
R
Miniello
Vito L
VL
Platzer
Michael H
MH
Rizzi
Domenica
D
Lospalluti
Maria Letizia
ML
Poulsen
Lars K
LK
Armenio
Lucio
L
Skov
Per Stahl
PS
D000293:Adolescent; D001323:Autoantibodies / Q000096:biosynthesis / Q000276:immunology*; D001327:Autoimmune Diseases / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D007223:Infant; D008297:Male; D015995:Prevalence; D017455:Receptors, IgE / Q000276:immunology*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014581:Urticaria / Q000276:immunology*
D001323:Autoantibodies; D017455:Receptors, IgE; D007073:Immunoglobulin E