Lower motor neuron facial palsy, also known as peripheral facial palsy or idiopathic facial paralysis, is a medical condition characterized by the weakness or paralysis of the facial muscles on one or both sides of the face due to damage or dysfunction of the lower motor neurons.
Lower motor neurons are responsible for carrying signals from the brain to the muscles, enabling voluntary control of facial movements such as smiling, frowning, or closing the eyes. When these neurons become damaged or impaired, the facial muscles they innervate are unable to receive proper nerve input, leading to weakness or complete paralysis of the affected muscles.
This condition often presents suddenly, and its exact causes are not always known. However, it may be associated with viral infections, such as herpes simplex virus or varicella-zoster virus, as well as certain autoimmune or inflammatory conditions. Other potential triggers include trauma, tumors, or the use of certain medications.
Symptoms of lower motor neuron facial palsy can include drooping of one side of the face, difficulty closing the eye on the affected side, drooling, loss of taste, and the inability to fully control facial expressions. Fortunately, most individuals with this condition experience spontaneous recovery within a few weeks to months, although a small percentage may have persistent facial weakness.
Treatment for lower motor neuron facial palsy may involve supportive measures such as eye protection, physical therapy, and the use of lubricating eye drops. In some cases, corticosteroids may be prescribed to reduce inflammation and promote healing.
