Bloch—Sulzberger syndrome (familial form of pigment incontinence) is a rare hereditary skin disease. Pigment incontinence belongs to systemic diseases and is characterized by specific changes in the skin and its appendages accompanied by nervous and musculoskeletal system pathology, as well as visual organ pathology. The disease is characterized by autosomal dominant inheritance. It is associated with a gene in the X-chromosome, exists since birth, and manifests within the first months of child’s life. This genetic pathology is characterized by staged course of clinical symptoms. The article reports a clinical case of two concomitant genetic diseases in an infant girl. Characteristic manifestations of the Bloch—Sulzberger syndrome in a child were described; it was noted that this pathology was first untimely diagnosed for a short time. Genetic skin diseases necessitate medical genetic counseling of patients, examination of relatives, and examination for comorbidities by appropriate specialists. When dermatologists are familiar with rare genetic syndromes, accurate diagnosis is possible in order to develop proper tactics of patient management. These patients receive symptomatic treatment with various topical drugs, depending on the stage of the disease.