Progressive hemifacial atrophy, also known as Parry-Romberg syndrome, is a progressive unilateral dystrophic disease of the facial tissues, with a few lesions involving the limbs or trunk. Progressive atrophy of muscle fibers does not involve cartilage and bone in severe cases. Most scholars believe that the disease is related to sympathetic nerve dysfunction caused by various causes of sympathetic nerve damage, resulting in neurotrophic impairment of facial tissues and eventually facial tissue atrophy. Other theories involve local or systemic infections and injuries, trigeminal neuritis, connective tissue disease, and genetic degeneration. Most scholars believe that the disease is related to sympathetic nerve dysfunction, which is caused by various causes of sympathetic nerve damage, resulting in neurotrophic disorders of facial tissues, and finally leading to facial tissue atrophy. Other theories involve local or systemic infections and injuries, trigeminal neuritis, and genetic degeneration of connective tissue disease. The rate of disease progression is variable most cases tend to remit after several to more than 10 years of progression but the accompanying epilepsy may continue. Epidemiology: Facial deviation atrophy (Parry-Romberg syndrome) begins most often in childhood and adolescence. It is usually between 10-20 years of age, but there is no absolute age limit. A more comprehensive incidence statistic has not been found for female patients. The cause of this syndrome is not yet known because some cases are associated with symptoms of cervical sympathetic disorder including Horner syndrome, which is generally considered to be related to central or peripheral damage to the autonomic nervous system. In addition, a few cases of the disease may be secondary to certain infections such as poliomyelitis, trauma, endocrine abnormalities, autoimmune diseases, etc. The muscles at the site of the lesion shrink due to the loss of fat and connective tissue, but the muscle fibers are not involved and their ability to contract is preserved. The subcutaneous fat and connective tissue of the facial lesions are the first to be involved, then the subcutaneous tissue of the skin, hair, and lipid glands are involved, and most severely the cartilage and bones of the skin and subcutaneous fat outside the face are involved. Small round cell infiltrates may be present in the ipsilateral cervical sympathetic nerve. Some cases are associated with atrophy of the cerebral hemispheres, which may be ipsilateral contralateral or bilateral. Individual cases are associated with hemiplegic atrophy. Biopsy shows atrophy of the papillary layer of the skin, fibrosis of the dermis and adipose tissue, and a decrease in lymphocyte and plasma cell infiltration of the muscle fibers. It has also been reported in the literature (Henta 1999) that facial nerve fiber atrophy and vacuolar degeneration were seen on electron microscopy as axonal degeneration. Clinical manifestations: 1. It occurs in adolescents before 20 years of age, occasionally within 1 year of age, and is more common in females, accounting for about 3/5. 3/4 of those with onset before 20 years of age have an insidious onset. In addition to facial atrophy, the soft palate, tongue and oral mucosa are often involved. 5% of cases involve both sides of the face, with occasional ipsilateral neck, chest, trunk and limb atrophy (about 10%). The affected side of the face is sunken in an elderly appearance, in contrast to the healthy side, and hair, eyebrows and eyelashes are often lost, and there are white spots and skin nevi. There may be facial pain or migraine, sensory disturbance is rare, except for the impaired regulation of sweat and lacrimal glands on the affected side, Horner’s syndrome is seen, a few patients have seizures, and about half of the patients have paroxysmal EEG activity. A few patients have seizures and about half of them have paroxysmal activity on EEG. Those with cerebral atrophy may have hemiparesis, hemianesthesia, hemianopsia, aphasia, etc. 2, the disease area shows limited subcutaneous fat and connective tissue atrophy skin atrophy, wrinkling, often accompanied by hair loss, hyperpigmentation, white spots, capillary dilation, increased or reduced sweat secretion, reduced saliva secretion, cheekbone forehead bone and other sunken and normal skin with a clear line of demarcation. 3, some cases and present pupillary changes, iris pigment reduction, eye sunken or protruding eye inflammation secondary glaucoma facial pain or mild diseased side hyperalgesia, facial muscle twitching, and endocrine disorders, etc., can progress with the course of the disease facial lateral atrophy and focal lipodystrophy is also often accompanied by skin sclerosis of a part of the body. When the lesioned limb and trunk are involved, the limb becomes thinner and shorter, the breast becomes smaller, the axillary hair becomes sparser and the organs become smaller, but the muscle strength is normal. In some cases, the atrophy invades the contralateral limb and is called crossed lateral atrophy. Complications: Only some patients have concomitant seizures or migraines, but about half of the patients have paroxysmal activity recorded on the EEG Diagnosis: The diagnosis is based on the specific facial morphology and imaging changes of the disease. The diagnosis is not difficult when the patient presents with typical unilateral facial atrophy, especially subcutaneous fat atrophy, occasionally spreading to the cranium, neck, shoulders and limbs without affecting muscle strength. Differential diagnosis: Only in the early stages, the following diseases need to be differentiated: 1. congenital lipodystrophy, also known as Lawrence-Seip syndrome. In infancy, the disease is often complicated by hypertrophy and sweating of the vulva and hirsutism of the head. The later development of diabetes mellitus can appear liver, renal insufficiency or cardiac hypertrophy, as well as the combination of acromegaly. 2, limited scleroderma The initial stage of the disease may produce confusion but the head and face is not a good site for scleroderma and skin scleroderma and the following tissue adhesions are very tight and not easy to pinch up, there is no knife scar type distribution can help distinguish. Laboratory tests: Blood, cerebrospinal fluid routine and biochemical tests are non-specific Other auxiliary tests: 1. 2. MRI or CT shows atrophic changes of bones, organs and cerebral hemispheres on the side of lesion. 3. EEG may show paroxysmal spike wave or slow wave activity. Treatment: There is no effective treatment for this disease, which is usually self-limiting and limited to symptomatic treatment. Some people use camptothecin (camptothecin hydrobromide) 5ml mixed with saline 10ml for facial acupoint injection, which can be effective in mild cases. Acupuncture, physiotherapy and massage can also be used. If you have epilepsy migraine trigeminal neuralgia eye inflammation should be given the appropriate treatment, serious cases can be cosmetic surgery Prognosis: The disease is usually self-limiting, the development of the disease to a certain extent will not progress Prevention: there is no effective preventive measures, mainly to prevent the possible causes of the original disease