Clinical, histologic, and cell kinetic discriminants between lamellar ichthyosis and nonbullous congenital ichthyosiform erythroderma

• Patients described as having lamellar ichthyosis (LI) may not all have the same disorder. We studied nine patients, four of whom had erythroderma and generalized fine scaling, while the remainder had more marked scaling and hyperkeratosis without erythema. The former group is referred to as having nonbullous congenital ichthyosiform erythroderma (CIE), and the other is said to have LI. The clinical differences were paralleled by cell kinetic and histologic differences. The mean tritiated thymidine autoradiographic labeling indices were 9.36 ± 4.05 and 19.70 ± 5.84 for the LI and CIE groups, respectively. The histologic differences were delineated using 10-cm analogue scales and showed statistically significant differences for hyperkeratosis and parakeratosis. These data support the hypothesis that LI and CIE are separate disorders. (Arch Dermatol1985;121:489-493)