title: Long-term response to hydroxychloroquine in patients with discoid lupus erythematosus.
abstract: BACKGROUND
  The recommended first-line oral therapy for discoid lupus erythematosus (DLE) is the antimalarial hydroxychloroquine. To the best of our knowledge, there is no published information regarding the long-term (i.e. > 6 months) response of DLE to hydroxychloroquine in clinical practice.
  
  
  OBJECTIVE
  To describe the long-term clinical response of DLE to hydroxychloroquine after 6 months of use.
  
  
  METHODS
  A multicentre retrospective cohort study was conducted in patients with DLE who had received treatment with hydroxychloroquine. All patients were recruited and interviewed by a single investigator and response to hydroxychloroquine assessed by the same individual through a retrospective review of case notes using a specified protocol.
  
  
  RESULTS
  A total of 200 patients with DLE were recruited (F:M = 4 : 1) with a median age at diagnosis of 40 years (range 16-81) and median follow-up of 8 years (range 0·5-37). An adequate clinical response to hydroxychloroquine was recorded in 91 patients (45·5%) but nonresponse occurred in 85 patients (42·5%). The remainder of patients either had partial response or withdrew from therapy due to toxicity or were unclassifiable. Importantly, of those individuals that did respond to hydroxychloroquine within the first 6 months of use, almost one in five eventually lost their response, despite continued administration, after a median interval of 2 years. These patients often regained disease control if treated with a combination of hydroxychloroquine and mepacrine. Of those that did not respond to hydroxychloroquine within the first 6 months of use, almost one in 10 became eventual responders either after continued administration for up to 2 years or when rechallenged on hydroxychloroquine. The remaining nonresponders relied frequently on oral corticosteroid.
  
  
  CONCLUSIONS
  In this cohort of patients with DLE, long-term clinical response to hydroxychloroquine occurred in less than 50% of patients. Nonresponders to hydroxychloroquine frequently required oral steroid to achieve disease control. These findings merit further investigation through a multicentre prospective study using a validated disease activity measure.
authors.affiliation: Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, NE2 4HH, U.K.
authors.forename: S
authors.initials: S
authors.lastname: Wahie
authors.forename: S J
authors.initials: SJ
authors.lastname: Meggitt
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003879:Dermatologic Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006886:Hydroxychloroquine / Q000627:therapeutic use*; D008134:Long-Term Care; D008179:Lupus Erythematosus, Discoid / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D003879:Dermatologic Agents; D006886:Hydroxychloroquine