title: Perforating granuloma annulare.
abstract: BACKGROUND
  Perforating granuloma annulare (PGA) is considered an histologic subtype of granuloma annulare (GA) and it is described as a very rare disease, usually of children, affecting the dorsum of the hands. Mechanisms leading to perforation are unknown. Our experience suggested a different clinical presentation, so we decided to review our patients and the cases published.
  
  
  METHODS
  We present six cases of PGA and review 52 PGA cases reported in the literature. Data regarding sex, age, time of evolution of disease, clinical features, laboratory findings, treatment, and follow-up were collected. The significance level was determined by the chi 2 or Student t test when appropriate.
  
  
  RESULTS
  The prevalence of PGA could be up to 5% of GA. Pustular-like lesions can be found in 26% of cases, and scars in 37%; papular, umbilicated, and crusted lesions being the most common finding. While PGA appears as a single lesion in only 9% of cases, and half of the patients are older than 30 years. In GA 50% of cases present as a single lesion and 80% of patients are younger than 30 years.
  
  
  CONCLUSIONS
  PGA is different to GA not only histologically but also clinically. It is a disseminated disease, affecting both children and adults, which is characterized by the presence of multiple papules, most of them umbilicated and/or crusted, and characteristically pustular lesions and scars. Histology suggests that the superficial localization of the necrobiotic granuloma leads to the epidermal perforation. Treatment is disappointing.
authors.affiliation: Department of Dermatology, Hospital Universitario de la Princesa, Madrid, Spain.
authors.forename: P F
authors.initials: PF
authors.lastname: Penas
authors.forename: M
authors.initials: M
authors.lastname: Jones-Caballero
authors.forename: J
authors.initials: J
authors.lastname: Fraga
authors.forename: J
authors.initials: J
authors.lastname: Sánchez-Pérez
authors.forename: A
authors.initials: A
authors.lastname: García-Díez
mesh_terms: D000328:Adult; D017668:Age of Onset; D001706:Biopsy; D003937:Diagnosis, Differential; D005260:Female; D016460:Granuloma Annulare / Q000453:epidemiology / Q000473:pathology* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence