Pityriasis rubra pilaris (PRP) is a dermatosis of unknown origin with a limited frequency in childhood (0.2% of our hospitalized pediatric patients). During the last 20 years we have observed 31 new cases; follow-up has been conducted in 29 children. The acute self-resolving form seems to be the most frequent in children, compared to adults. No cases of hereditary PRP have been observed, and no relationship between the severity of PRP and its prognosis has been reported. Since juvenile PRP has a relatively rapid course and a spontaneous resolution (a few months), it seems unnecessary to use potentially harmful drugs. Synthetic retinoids may be employed in patients whose disease is both persistent and disabling.

Lichen aureus is a rare asymptomatic dermatosis of unknown origin that is now classified in the group of pigmented purpuric dermatoses. The eruption consists of asymptomatic, roundish or irregular, lichenoid erythematous-purpuric papules with a tendency to coalesce in patches, most prevalent on the limbs. No meaningful laboratory abnormalities have been found. Histologically, the epidermis is normal, with a lymphohistiocytic, bandlike infiltrate with extravasated blood red cells and hemosiderin deposits observed in the dermis. During the last 20 years we have followed eight new patients, which represent 0.05% of our hospitalized patients. In five of eight patients the disease resolved in two to four years. No therapy has been carried out on these children, since lichen aureus has a tendency for slow, spontaneous improvement and resolution.

Papillon-Lefèvre syndrome (PLS) is a rare autosomal recessive genodermatosis characterized by the association of palmoplantar keratoderma with severe periodontopathy resulting in premature loss of both deciduous and permanent dentition. We treated a patient with PLS with etretinate and followed him for 10 years. Treatment was started at age 9 years, soon after the eruption of secondary dentition. Healing of cutaneous and periodontal lesions was obtained in a few months and maintained during the four years of treatment. Six years after etretinate withdrawal the teeth are still free of periodontal disease and firmly anchored to the alveolar bone. Our case confirms that retinoid therapy can positively influence the development of normal dentition in PLS when it is started during the eruption of the permanent teeth, and suggests that this result can be maintained for a long time even after stopping therapy.

To evaluate the clinical-effectiveness of etretinate in the treatment of papilloma virus infections, 20 children with extensive warts were given this oral retinoid for a period not exceeding three months at a dosage of 1 mg per kg per day. Sixteen patients showed complete regression of the disease without relapse, while in 4, lesions recurred after partial regression had been obtained. A follow-up of two years confirmed these findings. The results of this preliminary study are encouraging. Additional study is needed to determine the ultimate usefulness of etretinate in the treatment of refractory warts.