Oral retinoid therapy for disorders of keratinization: single-centre retrospective 25 years' experience on 23 patients.

BACKGROUND: Over the last three decades, the oral retinoids etretinate and acitretin have revolutionized the treatment of disorders of keratinization (DOK). Many patients with DOK require life-long treatment with oral retinoids. However, the longest follow-up data of patients with DOK on oral retinoid therapy is 10 years for adults and up to 11 years for children.
OBJECTIVES: The aim of our study was to collect long-term retrospective data including disease response, side-effects and pregnancy outcome in a cohort of patients with DOK who were among the first in the world to commence oral retinoids 25 years ago.
METHODS: Between 1979 and 1981, 30 patients with DOK were commenced on oral etretinate in our department. Case notes of these patients were reviewed retrospectively, and patients interviewed where possible to obtain the following information: diagnosis, age when treatment commenced, duration of treatment, reason for discontinuation of therapy, side-effects, abnormal investigation results and pregnancy outcomes.
RESULTS: Case notes of 23 of the 30 patients were available for review; of these, two patients were deceased and 14 were interviewed. In the 23 patients, the mean age of commencing treatment was 33.5 years (range 4.2-61) and the mean duration of etretinate therapy was 5.2 years (range 1 month to 14 years). Reasons for discontinuing treatment were an overall improvement in the skin disease (six of 23), no benefit +/- side-effects (11 of 23) and noncompliance (one of 23). Two patients died of causes unrelated to their skin disease or treatment, 12 and 4 years after stopping etretinate. Five patients (one female, four males) subsequently changed to acitretin and are currently continuing therapy. The mean total duration of retinoid therapy (etretinate and acitretin) for the four males was 23.7 years (range 20.6-25.1). The female patient continued intermittent courses (due to planned pregnancies) of oral retinoids for a total of 10.1 years over the last 25 years. Abnormal investigation results included elevated serum triglycerides and cholesterol (two of 23), isolated high triglycerides (three of 23), isolated high cholesterol (three of 23), worsening of liver enzymes in a patient with alcohol dependence, and elevated serum alkaline phosphatase (ALP) in healthy adults (three of 23). In two children, the elevated pretreatment ALP levels increased further after commencing etretinate but returned to normal in adulthood while treatment continued. One patient developed diffuse idiopathic skeletal hyperostosis after 21 years of retinoid therapy. One female patient had two early spontaneous abortions 2.75 and 3.2 years after discontinuing etretinate; she subsequently had two normal children. Two other females had normal children 1, 3 and 5 years after stopping etretinate. Two male patients fathered a total of three healthy children while on etretinate.
CONCLUSIONS: This study provides the longest available follow-up data of children and adults with DOK on oral retinoid therapy. Such information is essential for clinicians and their patients with DOK embarking on life-long treatment with retinoids.