title: Clinicopathologic correlation of hypocomplementemic and normocomplementemic urticarial vasculitis.
abstract: BACKGROUND
  Urticarial vasculitis is characterized by persistent urticarial lesions with histologic evidence of leukocytoclastic vasculitis. Hypocomplementemic urticarial vasculitis (HUV) is a distinct clinical entity in a subset of patients with urticarial vasculitis.
  
  
  OBJECTIVE
  We examined presentation of urticarial vasculitis and factors predictive of connective tissue disease.
  
  
  METHODS
  The clinical, histologic, and immunologic characteristics of 132 patients with urticarial vasculitis seen at the Mayo Clinic were examined, and features of the hypocomplementemic patients were compared with those of the normocomplementemic patients.
  
  
  RESULTS
  Twenty-four patients (18%) had hypocomplementemia; all were female. Interstitial dermal neutrophilia was seen in 19 biopsy specimens (83%). On direct immunofluorescence (DIF) testing of lesional skin, 23 patients (96%) had a continuous strong granular deposition of immunoreactants along the basement membrane zone compatible with lupus erythematosus in addition to vascular fluorescence. Systemic lupus erythematosus (SLE) was present or occurred in 13 (54%). One hundred eight patients (82%) had normocomplementemia; 65 (60%) were female. Interstitial dermal neutrophilia was seen in 11 of 26 (42%) randomly selected biopsy specimens. On DIF, one patient (1%) had the lupus band. SLE occurred in three patients (3%).
  
  
  CONCLUSIONS
  Patients with HUV were more likely to be female, to have diffuse neutrophilia on biopsy specimens stained with hematoxylin and eosin, to have continuous strong granular deposition of immunoreactants along the basement membrane zone on DIF, and to have SLE than normocomplementemic patients. We submit that HUV represents a subset of SLE with shared clinical, laboratory, and immunologic features.
authors.affiliation: Department of Dermatology, Mayo Clinic and Mayo Foundation Rochester, Minnesota 55905, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Davis
authors.forename: M S
authors.initials: MS
authors.lastname: Daoud
authors.forename: B
authors.initials: B
authors.lastname: Kirby
authors.forename: L E
authors.initials: LE
authors.lastname: Gibson
authors.forename: R S
authors.initials: RS
authors.lastname: Rogers
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003176:Complement C3 / Q000032:analysis; D003165:Complement System Proteins / Q000032:analysis* / Q000172:deficiency; D005260:Female; D019085:Fluorescent Antibody Technique, Direct; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000276:immunology / Q000473:pathology; D014581:Urticaria / Q000150:complications / Q000276:immunology* / Q000473:pathology*; D018366:Vasculitis, Leukocytoclastic, Cutaneous / Q000150:complications / Q000276:immunology* / Q000473:pathology*
chemical_list: D003176:Complement C3; D007075:Immunoglobulin M; D003165:Complement System Proteins