title: Chloroquine diphosphate: a risk factor for herpes zoster in patients with dermatomyositis/polymyositis.
abstract: OBJECTIVE
  Herpes zoster has been widely described in the context of different systemic autoimmune diseases but not dermatomyositis/polymyositis. Therefore, we analyzed the prevalence, risk factors and herpes zoster outcomes in this population.
  
  
  METHODS
  A retrospective cohort study of herpes zoster infections in dermatomyositis/polymyositis patients was performed. The patients were followed at a tertiary center from 1991 to 2012. For the control group, each patient with herpes zoster was paired with two patients without herpes zoster. Patients were matched by gender and the type of myositis, age at myositis onset and disease duration.
  
  
  RESULTS
  Of 230 patients, 24 (10.4%) had a histories of herpes zoster (19 with dermatomyositis and five with polymyositis, two-thirds female). The mean age of the patients with herpes zoster was 44.6±16.8 years. No difference between the groups was found regarding cumulative clinical manifestations. Disease activity, autoantibody, muscle and leukogram parameters were also comparable between the groups. No differences in immunosuppressive (alone or in association with other immunosuppressive therapies) or glucocorticoid (current use, medium dose and cumulative dose in the last two months) therapies were found between patients with and without herpes zoster. However, a higher proportion of patients in the herpes zoster group received chloroquine diphosphate compared to the control group. All of the patients received acyclovir; 58.3% of patients had postherpetic neuralgia and no cases of recurrence were reported. Furthermore, individuals who were taking high prednisone doses at the time of the herpes zoster diagnosis had reduced levels of postherpetic neuralgia.
  
  
  CONCLUSIONS
  These data suggest that chloroquine diphosphate could predispose patients with dermatomyositis/polymyositis to developing herpes zoster, particularly women and dermatomyositis patients.
authors.affiliation: Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, Rheumatology, São Paulo/SP, Brazil.
authors.forename: Gilmara Franco da
authors.initials: GF
authors.lastname: Cunha
authors.forename: Fernando Henrique Carlos de
authors.initials: FH
authors.lastname: Souza
authors.forename: Maurício
authors.initials: M
authors.lastname: Levy-Neto
authors.forename: Samuel Katsuyuki
authors.initials: SK
authors.lastname: Shinjo
mesh_terms: D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects* / Q000627:therapeutic use; D016022:Case-Control Studies; D002738:Chloroquine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D003882:Dermatomyositis / Q000150:complications / Q000188:drug therapy*; D005260:Female; D006562:Herpes Zoster / Q000139:chemically induced*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; C023676:chloroquine diphosphate; D002738:Chloroquine