Oral treatment of keratosis follicularis with a new aromatic retinoid.

Four patients with extensive keratosis follicularis (Darler's disease) showed excellent clinical response to the oral administration of a new aromatic derivative of retinoic acid (RO 10-9359). Initial oral treatment with 50 to 75 mg of the drug was followed by substantial improvement in four to seven days and the lesions cleared completely after three to four weeks. Long-term treatment with 25 to 30 mg/day was sufficient to prevent recurrence. No serious side effects were seen with this dosage after several months. Some dryness of the lips and the nasal mucosa occurred and one patient experienced slight nausea. Histological investigations showed the gradual disappearance of acantholysis, dyskeratosis, and hyperkeratosis, in this order. The given therapeutic schedule is a reliable routine management for keratosis follicularis in adults.