The causes of numbness in the lips include subjection of the lips to cold temperatures, certain medications, allergic reactions to foods and Raynaud’s phenomenon, explains Healthgrades. Tetany, which refers to contraction of muscles due to low blood calcium levels, cancer and hypothyroidism can cause numb lips.
Possible symptoms of numb lips include a burning or tingling sensation; bleeding; and redness, warmth or swelling of the lips, states Healthgrades. Accompanying symptoms, such as loss of balance and coordination, weakness in the muscles, problems with bowel movements, nausea or vomiting, unexpected face swelling, and difficulty with speech or swallowing may signal more serious conditions.
Poisonous chemicals, multiple sclerosis and ischemia, which is insufficient supply of blood to the lips, may lead to numbness in the lips, according to Healthgrades. Other causes include Guillain-Barré syndrome and Lyme disease.
In some cases, lip numbness may occur as a result of life-endangering conditions, including anaphylaxis, which refers to severe allergic reactions, notes Healthgrades. Eating toxic plants, intake of toxic chemicals, and hyperventilation may also result in serious numbness.
If left untreated, serious conditions for which numb lips are a symptom can cause lasting loss of sensation, brain damage, or difficulty with balance or coordination, states Healthgrades. A person suffering from numb lips may experience tingling or pain due to nerve problems. The individual should seek immediate medical attention if he suffers from numb lips that are life-threatening or if he experiences wheezing, difficulty breathing or swelling of the lips and surrounding areas.