Continuous 'microdose' isotretinoin in adult recalcitrant rosacea

Low‐dose isotretinoin is a well‐known treatment option in severe cases of rosacea.1 In 2000, Palmer et al.2 showed that continuous ‘microdose’ isotretinoin (CMI) treatment (0.04–0.11 mg/kg daily) was sufficient to control adult relapsing acne, but they mentioned that this is an unlicensed method of administration. Health insurance companies and public health systems often refuse to finance unlicensed methods of drug administration, even if they are effective and safe. It is therefore necessary to demonstrate the psychological benefits for the patients. In 1994, Finlay and Khan3 introduced the Dermatology Life Quality Index (DLQI), a practical questionnaire for routine clinical use. This test measures the extent of the disability caused by skin diseases. Ten questions cover symptoms and feelings, daily activities, leisure, personal relationships and treatment. The answers are scored between 0 and 3, resulting in a test score range of 0–30. Twelve patients (six men and six women, mean age 46.7 years), all with recalcitrant rosacea previously treated with topical metronidazole and several cycles of systemic antibiotics, are reported retrospectively (group 1). Initially, the patients received oral isotretinoin, 10 or 20 mg daily, over a period of 4 or 6 months. In response to the patients' fear of relapse at the end of therapy, isotretinoin was then reduced to an individual continuous minimal dose, with excellent results (Table 1). Experience showed that a lowering of this individually determined dose was promptly followed by a relapse. To measure the impact of the skin disease on their lives while on CMI maintenance treatment, a German translation of the DLQI questionnaire was sent to the patients in May 2003. All patients completed the questionnaire and gave consent for use of their personal files (group 1). A second group of 12 consecutive patients (four men and eight women, mean age 43.3 years) with different grades of untreated rosacea, seen in the private dermatological practice between April and June 2003, also completed the DLQI questionnaire (group 2). The replies were sorted according to sex and analysed anonymously. None of the patients in group 1, with rosacea controlled by CMI maintenance treatment (0.03–0.17 mg/kg daily; mean 0.07) (Table 1), reported any symptomatic side effects of CMI. Blood tests, carried out every 3 or 6 months, did not reveal any abnormalities. The mean DLQI score in group 1 was 1.16, in comparison with a mean score of 8.1 in the untreated group 2 (Table 2) (t‐test, P = 0.0001).