Background: Systemic isotretinoin has been known for decades to be effective in the treatment of severe forms of rosacea, but it must be used off-label because of the lack of evidence-based data.
Patients and methods: 573 patients with rosacea subtype II and III received one of three different dosages of isotretinoin (0.1 mg, 0.3 mg, or 0.5 mg per kg body weight), doxycycline (100 mg daily for 14 days, then 50 mg daily) or placebo in a double-blinded, randomized way for 12 weeks in 35 German centers.
Results: Isotretinoin 0.3 mg/kg proved to be the most effective dose with significant superiority versus placebo. Isotretinoin 0.3 mg/kg showed also significant non-inferiority versus doxycycline with reduction of lesions of 90 % compared to 83 % with doxycycline. Investigators diagnosed complete remission in 24 % and marked improvement in further 57 % of patients with isotretinoin treatment, in contrast to remission in 14 % and marked improvement in 55 % of patients treated with doxycycline. Isotretinoin 0.3 mg/kg revealed a similar safety profile as for the treatment of acne. Isotretinoin 0.5 mg/kg showed more dermatitis facialis as compared to 0.3 mg/kg.
Conclusions: Isotretinoin 0.3 mg/kg is an effective and well-tolerated therapy option for the treatment of rosacea subtype II and III and can therefore be used successfully as an alternative to therapy with oral antibiotics.