In published clinical studies using topical tretinoin, most of the 759 patients evaluated have received up to 6 months of therapy; therefore, long term studies would be helpful to determine the risk/benefits ratio of treatment. Recently, Elbs et al. have reported the effects of 22 months of therapy in 16 patients. Except for the commonly reported cutaneous retinoid reaction (peeling, burning sensation and erythema), no other adverse reactions were recorded, and the patients were able to sustain the clinical improvement in visible signs of photodamage. Similar findings have been recorded in the tretinoin emollient cream studies (unpublished data). Of a total of 619 patients enrolled in the tretinoin emollient cream studies. 305, 212 and 82 patients remained on 0.05% tretinoin emollient cream for 6, 12 and 18 months, respectively. Mild cutaneous retinoid reactions were recorded in 50~60% of patients. The incidence peaked at 2 weeks und then gradually declined over the following 12 months. The cutaneous side effects, although frequent, were rated as mild by both the investigators and the patients, and after treatment for 18 months only 5% of the patients had discontinued the treatment because of adverse experiences.

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