title: A 9-year-old boy with chronic urticaria and progressive spondyloarthritis.
abstract: A 9-year-old African American boy presented with chronic urticaria and progressive spondyloarthritis. Laboratory tests were abnormal for persistently positive antinuclear antibodies and undetectable total hemolytic complement (CH50) despite normal levels of complement C2, C3, and C4.  Ultimately, further testing revealed an underlying deficiency in the immune system that may be associated with autoimmune disease and thus have a bearing on the patient's urticaria and spondyloarthritis. This is a unique presentation of a rare disease and underscores the importance of evaluating  for systemic disease in the workup of chronic urticaria.
authors: Children's Foundation Research Institute at Le Bonheur Children's Hospital, University of Tennessee Health Science Center, Memphis, TN, USA.
authors: Dai
authors: D
authors: Park
authors: Monica L
authors: ML
authors: Brown
authors: Peter
authors: P
authors: Densen
authors: Linda K
authors: LK
authors: Myers
authors: D Betty
authors: DB
authors: Lew
mesh_terms: D000974:Antibodies, Antinuclear / Q000097:blood; D002648:Child; D002908:Chronic Disease; D015941:Complement Hemolytic Activity Assay; D003165:Complement System Proteins / Q000172:deficiency; D003937:Diagnosis, Differential; D018450:Disease Progression; D006801:Humans; D007596:Joints / Q000276:immunology*; D008297:Male; D017455:Receptors, IgE / Q000276:immunology; D012698:Serologic Tests; D013167:Spondylitis, Ankylosing / Q000175:diagnosis* / Q000209:etiology; D014581:Urticaria / Q000150:complications / Q000175:diagnosis*
chemical_list: D000974:Antibodies, Antinuclear; D017455:Receptors, IgE; D003165:Complement System Proteins