Are hyperlinear palms and dry skin signs of a concomitant autosomal ichthyosis vulgaris in atopic dermatitis?

In 30% to 40% of cases atopic dermatitis (AD) is believed to be associated with autosomal dominant ichthyosis vulgaris (ADI). The diagnosis of ADI can be proved by the ultrastructural demonstration of a defective keratohyalin (KH) synthesis, resulting in minute granules of crumbly appearance in only one layer of granular cells. To investigate the suggested frequent association of ADI with AD, ultrastructural examination of dry skin of 49 AD patients was performed. Only in 2 patients abnormal KH was demonstrated by electron microscopy. 17 patients, including the 2 patients with abnormal KH, showed hyperlinear palms. The present study shows that hyperlinear palms and dry skin are in most cases a phenotypic marker of AD alone and not a sign of concomitant ADI. A histologically one-layered or absent stratum granulosum may occur in the dry skin of patients with only AD and does not indicate a manifestation of concomitant ADI in all cases.