Randomized clinical trial to compare the efficacy of different doses of oral isotretinoin 10 mg/day, 20 mg/day and 30 mg/day during 12 weeks for the treatment of facial recalcitrant flat warts. The primary endpoint will be the proportion of participants with total remission of facial flat warts at the end of the intervention in the three arms of the clinical trial.

The investigators will recruit 162 participants with facial recalcitrant flat warts and randomize to the following three arms of intervention: Arm 1: nne capsule of isotretinoin 10 mg plus one capsule of placebo, per day during 12 weeks; Arm 2: one capsule of isotretinoin 20 mg plus one capsule of placebo, per day during 12 weeks; and Arm 3: one capsule of isotretinoin 10 mg plus one capsule of isotretinoin 20 mg, per day during 12 weeks. The primary endpoints will be the proportion of participants with total remission of facial flat warts at the end of the intervention in the three arms of the clinical trial; and the incidence of side effects related to oral isotretinoin treatment among the 3 arms of treatment.

Inclusion Criteria:

• Clinical and histological diagnosis of facial flats warts
• More than 2 years with facial flat warts
• Without response to 2 or more topical interventions (tretinoin, imiquimod, cryosurgery and 5-fluorouracil) or oral interventions (cimetidine or zinc sulfate)

Exclusion Criteria:

• Have the following conditions:

  1. Hypercholesterolemia
  2. Hypertriglyceridemia
  3. Liver disease
  4. Renal disease
  5. Sjögren syndrome
  6. Pregnancy
  7. Lactation
  8. Depressive disorder
  9. Body mass index less than 18 points or higher than 25 points
  10. Contraindications for hormonal contraception or intrauterine device.

All the interventions will be similar in appearance and all the participants will take the same quantity of capsules.