Parry Romberg syndrome (PRS), also known as progressive hemifacial atrophy, is a rare, acquired neurological disorder. It is characterized by the progressive deterioration and shrinkage of tissues on one side of the face. Symptoms typically start during childhood or adolescence, most frequently affecting females. PRS is considered a neurocutaneous syndrome because it involves both the nervous system and the skin. Estimates suggest it may affect approximately one in 250,000 people.
Defining Progressive Facial Atrophy
The primary physical characteristic of Parry Romberg syndrome is the gradual atrophy of various facial tissues, creating a noticeable asymmetry. This atrophy can involve subcutaneous fat, muscle, cartilage, and even bone structures. Tissue loss usually begins in the area supplied by one or more branches of the trigeminal nerve, often starting around the cheek or forehead.
The severity of facial indentation varies widely, ranging from mild fat loss to severe disfigurement involving the entire half of the face. Atrophy frequently impacts the cheek, jawline, and the area around the eye, causing a sunken appearance. When atrophy is severe, the mouth and nose may appear to deviate toward the affected side of the face.
Atrophy can also affect structures within the mouth, such as the tongue and the soft palate. Dental complications are common, including shorter tooth roots, delayed tooth eruption, or exposure of dental roots. The degree of atrophy is often classified as mild, moderate, or severe, based on how many divisions of the trigeminal nerve territory are involved. Bony atrophy indicates the most severe form.
The Disease Course and Related Conditions
Parry Romberg syndrome follows a specific pattern of progression divided into two main phases. The “active phase” involves the gradual progression of tissue atrophy, often lasting between two and 20 years. Following this, the disease typically enters a stable phase, where the progression of tissue loss spontaneously halts.
PRS is often associated with other symptoms involving the nervous system and the eyes. Neurological complications occur in a significant percentage of cases, including focal seizures, chronic headaches, or trigeminal neuralgia (severe facial pain). Imaging studies, such as MRI, may reveal abnormalities like white matter lesions or calcifications in the brain, even without overt neurological symptoms.
Ocular involvement is frequent, affecting up to 35% of individuals. The most common finding is enophthalmos, the recession of the eyeball into the socket caused by soft tissue loss around the orbit. Other associated issues include ptosis (drooping of the upper eyelid) and uveitis (inflammation of the eye’s middle layer).
Etiology and Diagnostic Process
The precise cause of Parry Romberg syndrome remains unknown, leading it to be described as an idiopathic disorder. The most widely accepted theory suggests an autoimmune mechanism. This is supported by the disorder’s similarities to localized scleroderma (morphea) and the presence of certain auto-antibodies in some affected individuals.
Other hypotheses point to possible dysfunction of the sympathetic nervous system, localized inflammation of blood vessels (neuro-vasculitis), or a history of trauma or viral infection. Diagnosis is primarily clinical, based on the characteristic visual presentation of slowly progressive, localized hemifacial atrophy. A thorough physical examination and medical history review confirm the diagnosis and exclude other conditions.
Imaging techniques (CT and MRI scans) are often used to assess the full extent of soft tissue and bone involvement. These scans also help differentiate PRS from other conditions, such as linear scleroderma en coup de sabre (ECDS). If neurological symptoms, like seizures, are present, specialized tests such as an electroencephalogram (EEG) may be performed.
Treatment and Long-Term Management
There is currently no definitive cure for Parry Romberg syndrome; treatment focuses on managing associated symptoms and restoring facial contour. During the active phase, medical management often involves immunomodulatory therapy to slow progression. Corticosteroids are sometimes used as a first-line therapy, with other immunosuppressants considered for non-responsive cases.
Management of non-atrophy symptoms includes using anticonvulsant medications for controlling seizures and regular monitoring for ophthalmic complications. The main approach for addressing facial deformity is surgical reconstruction, typically deferred until the disease enters its quiescent phase. Waiting for the condition to stabilize (usually one to two years without progression) ensures stable long-term results.
The most common reconstructive technique is autologous fat grafting (lipofilling), where a patient’s own fat is harvested and injected to fill soft tissue defects. For more severe cases, microvascular free tissue transfer (transplanting a flap of tissue with its own blood supply) may be necessary to restore volume. Procedures such as bone grafts or implants may be used to reconstruct underlying facial structure in cases involving significant skeletal defects.