Upper lip twitching is caused by a sudden involuntary contraction of the muscle or muscle fibers in the lips or as a result of direct stimulation or injury, according to Health Hype. Lip twitches also result from tics, spasms and tremors. They are usually benign, but sometimes indicate an underlying condition.
Upper lip twitches occur in healthy people due to stress, fatigue, a heightened emotional state and excessive caffeine or alcohol consumption, Health Hype notes. A dietary deficiency, such as low potassium, can also be a cause.
Persistent lip twitching, particularly if accompanied by other signs and symptoms, can signal a medical condition, according to Health Hype. For example, upper lip twitching may be one of the effects of Tourette's syndrome, which also includes nose wrinkling, tongue movement, unusual blinking and behavioral issues. Parkinson's patients often experience twitching of the upper lip due to the tremors that are a major symptom of the disease. In people with Parkinson's, tremors typically occur while at rest and dissipate or disappear while performing activities, such as eating and speaking. Many people afflicted with essential tremor, which causes tremors throughout the body, often experience upper lip twitches.
Children frequently have benign upper lip twitches that resolve on their own by adulthood, according to Health Hype.