The considerable variety of diseases involving both the skin and the peripheral or central nervous system is due to the developmental relationship between skin and nervous system. Diseases of the nervous system resulting in skin changes comprise disorders of nails, hair, sweat and sebaceous glands as well as neuropathic ulcers in various manifestations. Neurocutaneous syndromes (phacomatoses) are nevoid systemic diseases comprising neurofibromatoses, tuberose sclerosis, ataxia telangiectasia, nevoid angiomatoses and other neurocutaneous disorders. Polytopic disorders of the skin and nervous system may be due to infectious diseases, diseases of the connective tissue, fat, inflammatory vascular and granulomatous disorders.