More than fifty nosological forms of ichthyosis are known, which are characterized by diffuse keratinization that leads to hyperkeratosis with the formation of scales. The most widespread form is common ichthyosis, characterized by its relatively mild course. The disease, occurring at an early age, affects the skin of the trunk and limbs in the form of layers of scales of different sizes and colors. Disseminated pilaris keratosis occurs on dry and rough skin. Hyperkeratosis is most pronounced on the extensor surfaces of the elbow and knee joints. The skin of the face, neck and flexor surfaces of large joints is free from rashes. The skin on the palms and soles have more lines than normal and slight powder-like peeling is observed. There are several clinical variants of ichthyosis vulgaris: xerodermia, simple ichthyosis, white and serpiginous ichthyosis. The disease continues throughout life, worsening in winter. The clinical manifestations of ichthyosis weaken during puberty. X-linked recessive ichthyosis is one of the rare forms of ichthyosis vulgaris (as an independent genetic variant). It clinically manifests in the first months of life by extensive lesions of the skin. The clinical presentation manifests fully as hyperkeratosis and squamosis only in boys. Mothers have no visible manifestations. In contrast to ichthyosis vulgaris, in X-linked ichthyosis the skin condition does not improve with age. There is a «dirty skin of the neck» symptom. This disease occurs in 1 of 2000—6000 men, and knowledge of its clinical presentation is important for the dermatologist. The article presents a clinical observation of the disease in a 14-years-old patient.