Bone changes in children on long-term treatment with etretinate.

Ten children with disorders of keratinization (ichthyosis, 4, pityriasis rubra pilaris, 2, psoriasis, 2, and palmoplantar keratoderma, 2) were treated with etretinate for 0.5 to 9.6 years. The children ranged from 1.5 to 15.7 years of age. The total dose of etretinate ranged from 700 to 52,596 mg and the maintenance dose, from 0.21 to 0.86 mg/kg/day. Radiographic skeletal surveys were performed at various stages during treatment or following treatment. Bone abnormalities were found in eight children. Six children had periosteal thickening, two periosteal bone resorption, two osteoporosis, three disc narrowing, and one slender long bones. Compared with age- and sex-matched normal controls, the children had decreased cortical bone thickness of the second left metacarpal bone. The children's physical growth and laboratory investigations were normal. We recommend that children on long-term etretinate therapy be investigated regularly for bone changes.