Follicular ichthyosis

The document describes a study of four patients with congenital follicular hyperkeratosis, a skin condition characterized by excessive keratin production at the hair follicles. Three of these patients also exhibited pseudoacanthosis nigricans, a skin condition that results in dark, velvety patches in body folds and creases, and two presented with facial abnormalities. The researchers conducted a series of analyses on skin specimens, including light microscopy, autoradiography, histochemistry, and scanning electron microscopy. They compared the findings with those from patients suffering from keratosis pilaris, another condition involving keratin buildup around hair follicles. The study concluded that the condition observed in the four patients represents a unique form of ichthyosis, which is a group of skin disorders characterized by dry, scaly skin, where the abnormal skin differentiation is primarily localized within the hair follicles.